[Fix #595 #612] Fix infinite loop when reverse searching for next definition

[OknoLombarda]

Fixes #595
Fixes #612

Fix infinite loop in clojure-match-next-def when typing metadata in def forms. Some more context here.

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[vemv]

Looking reasonable!

Some suggestions for code coverage, will eye the impl again afterwards

[vemv]

Great work!

I verified that if one discards the fix but keeps the tests, said tests indeed loop forever: https://app.circleci.com/pipelines/github/clojure-emacs/clojure-mode/261/workflows/9315c32d-6ac0-40e0-a7ef-e16eb51218d2/jobs/899