Add check-spelling

.github/actions/spelling/README.md

@@ -12,6 +12,7 @@ File | Purpose | Format | Info
 [line_forbidden.patterns](line_forbidden.patterns) | Patterns to flag in checked lines | perl regular expression (order matters, first match wins) | [patterns](https://github.com/check-spelling/check-spelling/wiki/Configuration-Examples%3A-patterns)
 [expect.txt](expect.txt) | Expected words that aren't in the dictionary | one word per line (sorted, alphabetically) | [expect](https://github.com/check-spelling/check-spelling/wiki/Configuration#expect)
 [advice.md](advice.md) | Supplement for GitHub comment when unrecognized words are found | GitHub Markdown | [advice](https://github.com/check-spelling/check-spelling/wiki/Configuration-Examples%3A-advice)
+[block-delimiters.list](block-delimiters.list) | Define block begin/end markers to ignore lines of text | line with _literal string_ for **start** followed by line with _literal string_ for **end** | [block ignore](https://github.com/check-spelling/check-spelling/wiki/Feature%3A-Block-Ignore#status)
 
 Note: you can replace any of these files with a directory by the same name (minus the suffix)
-and then include multiple files inside that directory (with that suffix) to merge multiple files.
+and then include multiple files inside that directory (with that suffix) to merge multiple files together.