Update contributor name in credits

CHANGELOG.txt

@@ -38,7 +38,7 @@ Changelog
  * Docs: Add development (contributing to Wagtail) documentation notes for development on Windows (Akua Dokua Asiedu)
  * Docs: Mention Wagtail’s usage of Django’s default user model by default (Temidayo Azeez)
  * Docs: Add links to treebeard documentation for relevant methods (Temidayo Azeez)
- * Docs: Add clarification on where to register entity plugins (ChickenF622)
+ * Docs: Add clarification on where to register entity plugins (Mark McOsker)
  * Docs: Fix logo in README not being visible in high-contrast mode (Benita Anawonah)
  * Docs: Improve 'first wagtail site' tutorial (Akua Dokua Asiedu)
  * Docs: Grammatical adjustments of `page models` usage guide (Damilola Oladele)

CONTRIBUTORS.rst

@@ -668,7 +668,7 @@ Contributors
 * Elizabeth Bassey
 * Suyash Singh
 * Temidayo Azeez
-* ChickenF622
+* Mark McOsker
 * Benita Anawonah
 * Anisha Singh
 

docs/releases/4.2.md

@@ -54,7 +54,7 @@ depth: 1
  * Add development (contributing to Wagtail) documentation notes for [development on Windows](development_on_windows) (Akua Dokua Asiedu)
  * Mention Wagtail’s usage of Django’s default user model by default (Temidayo Azeez)
  * Add links to treebeard documentation for relevant methods (Temidayo Azeez)
- * Add clarification on where to register entity plugins (ChickenF622)
+ * Add clarification on where to register entity plugins (Mark McOsker)
  * Fix logo in README not being visible in high-contrast mode (Benita Anawonah)
  * Improve 'first wagtail site' tutorial (Akua Dokua Asiedu)
  * Grammatical adjustments of `page models` usage guide (Damilola Oladele)