rust-status: error on non-existent files in file_set file_set here consists of the files that were explicitly specified on the command line. Erroring on them matches the behavior of Python status.

rust-status: explicitly track bad file types Before this, we silently skipped bad file types. Now, we check to see if a path is an exact_match in our matcher, and if so, print an error for it, and only then do we skip it. A path will be an exact match when it's specified as an explicit command line argument, and this error-printing behavior is necessary for compatibility with Python status.

rust: de-hardcode glob_suffix We're adding patternmatcher in a subsequent commit, and this needs needs to be different for includematcher and patternmatcher.