gh-100893: update bpo reference in Mac README (GH-100905)

Author: ned-deily

Mac/README.rst

@@ -347,9 +347,9 @@ The configure script sometimes emits warnings like the one below::
    configure: WARNING: libintl.h:     section "Present But Cannot Be Compiled"
    configure: WARNING: libintl.h: proceeding with the preprocessor's result
    configure: WARNING: libintl.h: in the future, the compiler will take precedence
-   configure: WARNING:     ## --------------------------------------- ##
-   configure: WARNING:     ## Report this to https://bugs.python.org/ ##
-   configure: WARNING:     ## --------------------------------------- ##
+   configure: WARNING:     ## -------------------------------------------------------- ##
+   configure: WARNING:     ## Report this to https://github.com/python/cpython/issues/ ##
+   configure: WARNING:     ## -------------------------------------------------------- ##
 
 This almost always means you are trying to build a universal binary for
 Python and have libraries in ``/usr/local`` that don't contain the required