Merge pull request matplotlib#28645 from meeseeksmachine/auto-backport-of-pr-28644-on-v3.9.x

Backport PR matplotlib#28644 on branch v3.9.x (DOC: Fix matching for version switcher)

Author: tacaswell

doc/conf.py

@@ -496,10 +496,9 @@ def js_tag_with_cache_busting(js):
             f"https://matplotlib.org/devdocs/_static/switcher.json?{SHA}"
         ),
         "version_match": (
-            # The start version to show. This must be in switcher.json.
-            # We either go to 'stable' or to 'devdocs'
-            'stable' if matplotlib.__version_info__.releaselevel == 'final'
-            else 'devdocs')
+            matplotlib.__version__
+            if matplotlib.__version_info__.releaselevel == 'final'
+            else 'dev')
     },
     "navbar_end": ["theme-switcher", "version-switcher", "mpl_icon_links"],
     "navbar_persistent": ["search-button"],