Fix typo

[CI skip]

Co-Authored-By: Andrew Murray <3112309+radarhere@users.noreply.github.com>

Author: hugovk

docs/releasenotes/7.1.1.rst

@@ -4,7 +4,7 @@
 Fix regression seeking PNG files
 ================================
 
-This fixes a regression introduced 7.1.0 when adding support for APNG files when calling
+This fixes a regression introduced in 7.1.0 when adding support for APNG files when calling
 ``seek`` and ``tell``:
 
 .. code-block:: python