[3.10] Fix typo in whatsnew 3.10.rst (GH-26854) (GH-28782)

Thanks for the fix @wiggin15 .
(cherry picked from commit 599c070)


Co-authored-by: Arnon Yaari <[email protected]>

Automerge-Triggered-By: GH:JulienPalard

Author: miss-islington

Doc/whatsnew/3.10.rst

@@ -1584,7 +1584,7 @@ Deprecated
   this release, a deprecation warning is raised if the numeric literal is
   immediately followed by one of keywords :keyword:`and`, :keyword:`else`,
   :keyword:`for`, :keyword:`if`, :keyword:`in`, :keyword:`is` and :keyword:`or`.
-  If future releases it will be changed to syntax warning, and finally to
+  In future releases it will be changed to syntax warning, and finally to
   syntax error.
   (Contributed by Serhiy Storchaka in :issue:`43833`).