[3.13] gh-101100: Fix sphinx warnings in whatsnew/3.11.rst (GH-136402) (#136404)

Co-authored-by: Weilin Du <108666168+LamentXU123@users.noreply.github.com>

Author: miss-islington

Doc/tools/.nitignore

@@ -74,4 +74,3 @@ Doc/whatsnew/3.6.rst
 Doc/whatsnew/3.7.rst
 Doc/whatsnew/3.8.rst
 Doc/whatsnew/3.10.rst
-Doc/whatsnew/3.11.rst

Doc/whatsnew/3.11.rst

@@ -1292,7 +1292,7 @@ This section covers specific optimizations independent of the
   (Contributed by Stefan Behnel in :gh:`68264`.)
 
 * Resizing lists is streamlined for the common case,
-  speeding up :meth:`list.append` by ≈15%
+  speeding up :meth:`!list.append` by ≈15%
   and simple :term:`list comprehension`\s by up to 20-30%
   (Contributed by Dennis Sweeney in :gh:`91165`.)