Fix outdated lies in "Script and Regex" linter documentation

Summary: See D14536. Some time ago, linters changed to no longer receive these special/unusual file types as inputs by default.

Test Plan:

• Read new docs.
• Attempted to grep for other similar lies, although it's possible I missed some. I didn't find anything.

Reviewers: bgamari, chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D14543