match: introduce uipath() to properly style a file path Several methods print files relative to the repo root, unless files are named on the command line, in which case they are printed relative to cwd. Since the check relies on the 'pats' parameter, which needs to be replaced by a matcher when adding subrepo support, this logic gets folded into the matcher to tidy up the callers. Prior to 3778884197f0, this style decision was based off of whether or not the 'pats' list was empty. That change altered the check to test match.anypats() instead, in order to make paths printed consistent when -I/-X is specified. That however, changed the style when a file is given to the command. So now we test the pattern list to get the old behavior for files, as well as test -I/-X to get the consistency for patterns.