gh-135828: Disable syntax highlighting in Using Python on macOS

The page uses parsed-literal blocks for shell snippets so that
`|version|` substitutions work. Without an explicit highlight
language, Sphinx applies the project default (`python3`), which
makes the Pygments python3 lexer choke on tokens like `$` in the
shell examples. The English build silently retries in relaxed mode,
but translated builds (e.g. python-docs-pt-br) surface this as
`misc.highlighting_failure` warnings and add an unwanted highlight
to the rendered output.

Add `.. highlight:: none` at the top of the file, matching the
pattern already used by `Doc/using/windows.rst` and
`Doc/using/editors.rst`. The English HTML output is unchanged
(the page already rendered without highlight thanks to the lexer
fallback) and the translation builds no longer produce the warning.

Author: Taeknology

Doc/using/mac.rst

@@ -1,3 +1,4 @@
+.. highlight:: none
 
 .. _using-on-mac: