Add more icons to website headings and content tabs. (iree-org#15311)

This helps break up the text more. Content tabs are also easier to click
on with wider titles.


![image](https://github.com/openxla/iree/assets/4010439/46f5179b-c0f9-4fd2-a68a-2db112f047f7)

docs/website/docs/building-from-source/android.md

@@ -61,7 +61,7 @@ cmake --build ../iree-build/ --target install
 
 Build the runtime using the Android NDK toolchain:
 
-=== "Linux"
+=== ":fontawesome-brands-linux: Linux"
 
     ``` shell
     cmake -GNinja -B ../iree-build-android/ \
@@ -74,7 +74,7 @@ Build the runtime using the Android NDK toolchain:
     cmake --build ../iree-build-android/
     ```
 
-=== "macOS"
+=== ":fontawesome-brands-apple: macOS"
 
     ``` shell
     cmake -GNinja -B ../iree-build-android/ \
@@ -87,7 +87,7 @@ Build the runtime using the Android NDK toolchain:
     cmake --build ../iree-build-android/
     ```
 
-=== "Windows"
+=== ":fontawesome-brands-windows: Windows"
 
     ``` shell
     cmake -GNinja -B ../iree-build-android/ \

docs/website/docs/building-from-source/getting-started.md

@@ -15,7 +15,7 @@ recommend the [Ninja](https://ninja-build.org/) CMake generator and the
     configurations (including the Makefile generator and gcc) are "best effort".
     Patches to improve support are always welcome.
 
-=== "Linux"
+=== ":fontawesome-brands-linux: Linux"
 
     1. Install a compiler/linker (typically "clang" and "lld" package)
 
@@ -30,7 +30,7 @@ recommend the [Ninja](https://ninja-build.org/) CMake generator and the
     sudo apt install cmake ninja-build clang lld
     ```
 
-=== "macOS"
+=== ":fontawesome-brands-apple: macOS"
 
     1. Install [CMake](https://cmake.org/download/)
 
@@ -42,7 +42,7 @@ recommend the [Ninja](https://ninja-build.org/) CMake generator and the
     brew install cmake ninja
     ```
 
-=== "Windows"
+=== ":fontawesome-brands-windows: Windows"
 
     1. Install MSVC from Visual Studio or "Tools for Visual Studio" on the
        [official downloads page](https://visualstudio.microsoft.com/downloads/)
@@ -96,7 +96,7 @@ settings can improve compile and link times substantially.
 
 <!-- TODO(#5804): add notes about CMake presets?  -->
 
-=== "Linux"
+=== ":fontawesome-brands-linux: Linux"
 
     ``` shell
     # Recommended development options using clang and lld:
@@ -110,7 +110,7 @@ settings can improve compile and link times substantially.
         -DIREE_ENABLE_LLD=ON
     ```
 
-=== "macOS"
+=== ":fontawesome-brands-apple: macOS"
 
     ``` shell
     # Recommended development options using clang and lld:
@@ -127,7 +127,7 @@ settings can improve compile and link times substantially.
     `CMAKE_AR` variable is defined and points to the path of either the GNU
     binutils or LLVM `ar` program, overriding the default Apple `ar`.
 
-=== "Windows"
+=== ":fontawesome-brands-windows: Windows"
 
     ``` shell
     # Recommended development options:
@@ -267,7 +267,7 @@ You will need a recent Python installation >=3.9 (we aim to support
 ???+ Tip "Tip - Managing Python versions"
     Make sure your 'python' is what you expect:
 
-    === "Linux"
+    === ":fontawesome-brands-linux: Linux"
 
         Note that on multi-python systems, this may have a version suffix, and on
         many Linuxes where python2 and python3 can co-exist, you may also want to
@@ -278,7 +278,7 @@ You will need a recent Python installation >=3.9 (we aim to support
         python --version
         ```
 
-    === "macOS"
+    === ":fontawesome-brands-apple: macOS"
 
         Note that on multi-python systems, this may have a version suffix, and on
         macOS where python2 and python3 can co-exist, you may also want to use `python3`.
@@ -288,7 +288,7 @@ You will need a recent Python installation >=3.9 (we aim to support
         python --version
         ```
 
-    === "Windows"
+    === ":fontawesome-brands-windows: Windows"
         The
         [Python launcher for Windows](https://docs.python.org/3/using/windows.html#python-launcher-for-windows) (`py`) can help manage versions.
 
@@ -304,21 +304,21 @@ You will need a recent Python installation >=3.9 (we aim to support
     ([about](https://docs.python.org/3/library/venv.html),
     [tutorial](https://docs.python.org/3/tutorial/venv.html)):
 
-    === "Linux"
+    === ":fontawesome-brands-linux: Linux"
 
         ``` shell
         python -m venv .venv
         source .venv/bin/activate
         ```
 
-    === "macOS"
+    === ":fontawesome-brands-apple: macOS"
 
         ``` shell
         python -m venv .venv
         source .venv/bin/activate
         ```
 
-    === "Windows"
+    === ":fontawesome-brands-windows: Windows"
 
         ``` powershell
         python -m venv .venv
@@ -356,23 +356,23 @@ cmake --build ../iree-build/
 
 Extend your `PYTHONPATH` with IREE's `bindings/python` paths and try importing:
 
-=== "Linux"
+=== ":fontawesome-brands-linux: Linux"
 
     ``` shell
     source ../iree-build/.env && export PYTHONPATH
     python -c "import iree.compiler"
     python -c "import iree.runtime"
     ```
 
-=== "macOS"
+=== ":fontawesome-brands-apple: macOS"
 
     ``` shell
     source ../iree-build/.env && export PYTHONPATH
     python -c "import iree.compiler"
     python -c "import iree.runtime"
     ```
 
-=== "Windows"
+=== ":fontawesome-brands-windows: Windows"
 
     ``` powershell
     ../iree-build/.env.bat

docs/website/docs/building-from-source/ios.md

@@ -15,7 +15,7 @@ Cross-compilation for iOS consists of the two steps below.
 * Build the IREE runtime on the macOS host for iOS devices and the
   simulator.  We can then run the IREE module on the simulator.
 
-## Prerequisites
+## :octicons-download-16: Prerequisites
 
 ### Install Xcode and iOS SDK
 
@@ -30,9 +30,9 @@ On your host platform, you should already be able to build IREE from
 source.  Please make sure you've gone through the steps in [getting
 started](./getting-started.md).
 
-## Configure and Build
+## :octicons-sliders-16: Configure and build
 
-### Build the IREE Compiler for the Host
+### Build the IREE compiler for the Host
 
 Build and install on your macOS host:
 
@@ -44,7 +44,7 @@ cmake -S . -B ../iree-build/ -GNinja \
 cmake --build ../iree-build/ --target install
 ```
 
-## Cross-compile the IREE Runtime for iOS
+### Cross-compile the IREE runtime for iOS
 
 Build the runtime for the iOS Simulator.
 
@@ -70,7 +70,7 @@ of the `-DCMAKE OSX SYSROOT` option to:
   -DCMAKE_OSX_SYSROOT=$(xcodebuild -version -sdk iphoneos Path)
 ```
 
-## Running IREE Modules on the iOS Simulator
+## :octicons-code-16: Running IREE modules on the iOS Simulator
 
 Run the IREE compiler on the host to generate a module.
 

docs/website/docs/building-from-source/riscv.md

@@ -17,7 +17,7 @@ and operating system):
 * IREE's _runtime_ is built on the host for the target. The runtime is then
   pushed to the target to run natively.
 
-## Prerequisites
+## :octicons-download-16: Prerequisites
 
 ### Host environment setup
 
@@ -61,7 +61,7 @@ from the IREE root directory:
 For RISC-V vector extensions support, see
 [additional instructions](#optional-configuration)
 
-## Configure and build
+## :octicons-sliders-16: Configure and build
 
 ### Host configuration
 
@@ -98,7 +98,7 @@ cmake -GNinja -B ../iree-build-riscv/ \
 cmake --build ../iree-build-riscv/
 ```
 
-## Running IREE bytecode modules on the RISC-V system
+## :octicons-code-16: Running IREE bytecode modules on the RISC-V system
 
 !!! note
     The following instructions are meant for the RISC-V 64-bit Linux

docs/website/docs/guides/deployment-configurations/gpu-vulkan.md

@@ -40,7 +40,7 @@ verified by the following steps:
     Android mandates Vulkan 1.1 support since Android 10. You just need to
     make sure the device's Android version is 10 or higher.
 
-=== "Linux"
+=== ":fontawesome-brands-linux: Linux"
 
     Run the following command in a shell:
 
@@ -56,7 +56,7 @@ verified by the following steps:
     If the listed version is lower than Vulkan 1.2, you will need to update the
     driver for your GPU.
 
-=== "Windows"
+=== ":fontawesome-brands-windows: Windows"
 
     Run the following command in a shell:
 

docs/website/docs/reference/bindings/python.md

@@ -36,21 +36,21 @@ To use IREE's Python bindings, you will first need to install
     ([about](https://docs.python.org/3/library/venv.html),
     [tutorial](https://docs.python.org/3/tutorial/venv.html)):
 
-    === "Linux"
+    === ":fontawesome-brands-linux: Linux"
 
         ``` shell
         python -m venv .venv
         source .venv/bin/activate
         ```
 
-    === "macOS"
+    === ":fontawesome-brands-apple: macOS"
 
         ``` shell
         python -m venv .venv
         source .venv/bin/activate
         ```
 
-    === "Windows"
+    === ":fontawesome-brands-windows: Windows"
 
         ``` powershell
         python -m venv .venv