Use wildcard label filters to simplify triaging.md

triaging.md has a lot of queries that enumerate all labels in a category, like all the "T-" or "C-" labels.  It would be nice to filter these all out with a wildcard label search.  Unfortunately, GitHub doesn't support this yet.  I'm opening this issue to track this feature request if GitHub implements it.

https://github.com/isaacs/github/issues/1553