PEP 7: Prohibit compiler extensions in general, not just GCC, per pyt…

…hon#758

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

pep-0007.txt

@@ -50,8 +50,8 @@ C dialect
   Future C99 features may be added to this list in the future
   depending on compiler support (mostly significantly MSVC).
 
-* Don't use GCC extensions (e.g. don't write multi-line strings
-  without trailing backslashes).
+* Don't use compiler-specific extensions, such as those of GCC or MSVC
+  (e.g. don't write multi-line strings without trailing backslashes).
 
 * All function declarations and definitions must use full prototypes
   (i.e. specify the types of all arguments).