Add ReCheck to CI?

Commit 6e65445 modified a bunch of regexes to try and implement redos mitigation. Since then, tools have appeared to try and find out if regexes are sensible to the issue (using both fuzzing and modelling). https://makenowjust-labs.github.io/recheck/ is available as a javascript & scala library and should be reasonably easy to integrate into a CI script.