Issue #27076: Doc, comment and test function name spelling fixes

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 9b5f62d..7b85268 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1919,7 +1919,7 @@
 #endif
 }
 
-/* Deprecated C API functions still provided for binary compatiblity */
+/* Deprecated C API functions still provided for binary compatibility */
 
 #undef PyParser_SimpleParseFile
 PyAPI_FUNC(node *)