DOC: Update doc URL in setup.cfg (for 1.5.x) (#50279)

Author: jakirkham

setup.cfg

@@ -26,7 +26,7 @@ classifiers =
     Topic :: Scientific/Engineering
 project_urls =
     Bug Tracker = https://github.com/pandas-dev/pandas/issues
-    Documentation = https://pandas.pydata.org/pandas-docs/stable
+    Documentation = https://pandas.pydata.org/docs/
     Source Code = https://github.com/pandas-dev/pandas
 
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