Fringe indicators for sucessful/failed tests

[vemv]

Context

When working with tests frequently, one can forget if a given test failed, succeeded, or if it was run at all.

We have tech for 'fringe' indicators, i.e. these white things:

Proposal

After running tests, any deftest top-level forms that were run get a green/red fringe indicator.

Notes

Sample code to get started:

(cider--make-fringe-overlays-for-region (point) (save-excursion (end-of-buffer) (point)))

This introduces fringes of the 'cider-fringe-indicator type. We should introduce new types instead e.g. cider-successful-test-fringe-indicator.

[vemv]

Simply jotting down something I could implement some other day (but the feature is also up for grabs)