src/sage_docbuild/ext/sage_autodoc.py: Fix docstring for 'tox -e rst'

Author: Matthias Koeppe

src/sage_docbuild/ext/sage_autodoc.py

@@ -113,7 +113,7 @@ def identity(x: Any) -> Any:
 
 
 class _All:
-    """A special value for :*-members: that matches to any member."""
+    """A special value for ``:*-members:`` that matches to any member."""
 
     def __contains__(self, item: Any) -> bool:
         return True