Revert "ci: add check-spelling GitHub Action"

This reverts commit aef393bdce.

.github/actions/spelling/excludes.txt

@@ -1,17 +0,0 @@
-# See https://github.com/check-spelling/check-spelling/wiki/Configuration-Examples:-excludes
-(?:^|/)(?i)COPYRIGHT
-(?:^|/)(?i)LICEN[CS]E
-(?:^|/)package(?:-lock|)\.json$
-(?:^|/)vendor/
-ignore$
-\.avi$
-\.ico$
-\.jpe?g$
-\.lock$
-\.map$
-\.min\.
-\.mod$
-\.mp[34]$
-\.png$
-\.wav$
-^\.github/