Add support for mapping `jk` to escape in vim mode.
This changes the behaviour of the keymatches when there are pending
matches.
Before: Even if there was a pending match, any complete matches would be
triggered and the pending state lost.
After: If there is a pending match, any complete matches are delayed by
1s, or until more keys are typed.
Release Notes:
- Added support for mapping `jk` in vim mode
([#2378](https://github.com/zed-industries/community/issues/2378)),
([#176](https://github.com/zed-industries/community/issues/176))
Conrad Irwin
72cb865108