Fix tests with Python 3.13

Properly implement the iterator protocol.

pygit2/config.py

@@ -52,19 +52,16 @@ def __del__(self):
     def __iter__(self):
         return self
 
+    def __next__(self):
+        return self._next_entry()
+
     def _next_entry(self):
         centry = ffi.new('git_config_entry **')
         err = C.git_config_next(centry, self._iter)
         check_error(err)
 
         return ConfigEntry._from_c(centry[0], self)
 
-    def next(self):
-        return self.__next__()
-
-    def __next__(self):
-        return self._next_entry()
-
 
 class ConfigMultivarIterator(ConfigIterator):
     def __next__(self):

pygit2/index.py

@@ -467,8 +467,8 @@ def __init__(self, index):
     def __del__(self):
         C.git_index_conflict_iterator_free(self._iter)
 
-    def next(self):
-        return self.__next__()
+    def __iter__(self):
+        return self
 
     def __next__(self):
         cancestor = ffi.new('git_index_entry **')
@@ -486,6 +486,3 @@ def __next__(self):
         theirs = IndexEntry._from_c(ctheirs[0])
 
         return ancestor, ours, theirs
-
-    def __iter__(self):
-        return self

pygit2/utils.py

@@ -165,8 +165,8 @@ def __init__(self, container):
         self.length = len(container)
         self.idx = 0
 
-    def next(self):
-        return self.__next__()
+    def __iter__(self):
+        return self
 
     def __next__(self):
         idx = self.idx