gh-156995: Fix typo in the _PyBytes_Resize() NEWS entry

Co-authored-by: Cody Maloney <cmaloney@users.noreply.github.com>

Author: vstinner

Misc/NEWS.d/next/C_API/2026-09-12-21-00-42.gh-issue-156995.UVjqQe.rst

@@ -1,3 +1,3 @@
 On Free Threading, ``_PyBytes_Resize(&obj, 1)`` no longer returns a single byte
-singleton is the current thread is different than the thread which created the
+singleton if the current thread is different than the thread which created the
 object. Patch by Stan Ulbrych.