Simplifiy the definition of the refreshed regions and document why we refresh all region types.
Don't set the GOGC env var for margo. I don't think it's useful anymore.
Give each command their own uid when they start so the same unique value can be re-used outside if exec_c()
Add function gs.uid_seq() to a pair of uid and the corresponding numeric value to avoid the need for comparing uid values
Expose the sequence number for each command's uid to make comparing them simpler.
Allow a caller of kv.M.filter to specify the list of keys
* Undo the previous change that did highlight clearing in a command's start() method.
This didn't work because often a command's highlighting context is only determined after the
command starts, e.g. in the `go` command, it's defind by the command itself.
* Always update the highlights on command output and completion, even if we know there are no new highlights.
This fix any issue where highlights appear to stay forever even after the linter runs again.
* do_hl is now aware of stale highlights so we should no longer end up in situations
where a slow instance of a command completes after a newer one and causes invalid highlights to appear.