Fix --help with python 3.14 and sphinx 8.2.3

The sphinx help strings assert the existence of translations, which are
not provided by sphinx-autobuild.  Convert the _TranslationProxy
objects into English strings.

Author: jamesjer

sphinx_autobuild/__main__.py

@@ -147,6 +147,10 @@ def _get_sphinx_build_parser():
     sphinx_build_parser.description = None
     sphinx_build_parser.epilog = None
     sphinx_build_parser.prog = "sphinx-autobuild"
+    for action in sphinx_build_parser._actions:
+        if hasattr(action, "help"):
+            # Replace _TranslationProxy objects with strings
+            action.help = str(action.help)
     for action in sphinx_build_parser._actions:
         if hasattr(action, "version"):
             # Fix the version