Plugin tweaks: Ensure gutenberg element styles are only generated once.

This fixes a compat issue between WP trunk and Gutenberg 17.9-18.2, where element styles (e.g., link colors) added to blocks are not attached correctly.

See WordPress/wporg-parent-2021#135

mu-plugins/plugin-tweaks/gutenberg.php

@@ -11,6 +11,10 @@
 add_filter( 'render_block_core/query-title', __NAMESPACE__ . '\swap_h0_for_paragraph', 20 );
 add_filter( 'wp_script_attributes', __NAMESPACE__ . '\inject_module_cachebuster' );
 
+// Remove duplicate elements generation, can be removed after GB18.3+ is active.
+// See https://github.com/WordPress/wporg-parent-2021/issues/135.
+remove_filter( 'render_block_data', 'wp_render_elements_support_styles', 10, 1 );
+
 /**
  * Replace invalid `h0` tags with paragraphs.
  *