Custom formatter for ex-info thrown by cljs.spec

Currently it's quite tricky to get good output from cljs.spec. Reason being that the ex-info thrown includes the full spec commentary in ex-message. This includes the serialised val which failed. In my case this can fill the console many times over.

Alex Miller recommended catching these exceptions and using the ex-data to present the spec nicely. (e.g. don't print the ex-message to the console). This would be fine except it's difficult to catch all errors due to the nature of how UI code executes (react render loop, re-frame dispatch queue, callbacks)

How about automatically detecting and pretty formatting ex-info errors thrown by cljs.spec?

The issue names no files, tests, or entry points. Start by locating where cljs-devtools handles uncaught errors from UI render loops, re-frame dispatch queues, and callbacks, then determine how cljs.spec ex-info can be identified and formatted without printing ex-message. Done means the behavior is defined and covered for the described error paths.

Written by the indexing model from the issue text.