help: eliminate duplicate text for revset string patterns There's no reason to duplicate this so many times, and it's likely an instance will be missed if support for a new pattern is added and documented. The stringmatcher is mostly used by revsets, though it is also used for the 'tag' related templates, and namespace filtering in the journal extension. So maybe there's a better place to document it. `hg help patterns` seems inappropriate, because that is all file pattern matching. While here, indicate how to perform case insensitive regex searches.