rust: use owned types in `Matcher`
This simplifies the code a lot, allows for some refactoring to come.
The original code tried to prevent allocations that were already happening
anyway beforehand.
#require test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint