Probably want to be able to read from STDIN or a file ...
All files should be checked for extension equivalents, and for lowercase or alternative-case variants.
- CHANGELOG
- CHANGES
- HISTORY
- NEWS
- RELEASES
- txt
- rst (restructuredtext)
- md (markdown) + variants
If a file extensions exists and it is notionally tied to a markup language, only consider that markup language. Other try any, I guess?