l0dables: fix CRT to allow overriding handlers

.weakref didn't do what I want, and the old construct ended up preventing us from overwriting interrupt handlers in l0dables.

This wastes some bytes (each handler is now implemented separately by default), but it works.

Looks good to me! Thanks for keeping our codebase clean.

However, I'm only a bot - so a human will still have to approve this request.

changed milestone to %v1.11

added 1-Bug label

added 6 - Needs Testing label

added 3-L0dables label

merged

mentioned in commit 78fd5bee