Only check changed files for spelling

Author: msimberg

.github/workflows/spelling.yaml

@@ -33,6 +33,7 @@ jobs:
         suppress_push_for_open_pull_request: ${{ github.actor != 'dependabot[bot]' && 1 }}
         checkout: true
         check_file_names: 0
+        only_check_changed_files: 1
         post_comment: 1
         use_magic_file: 1
         warnings: bad-regex,binary-file,deprecated-feature,large-file,limited-references,no-newline-at-eof,noisy-file,non-alpha-in-dictionary,token-is-substring,unexpected-line-ending,whitespace-in-dictionary,minified-file,unsupported-configuration,no-files-to-check