handlers: Use activeWhen rather than enabledWhen consistently and scope

[mickaelistria]

to languageServer

[mickaelistria]

Thanks!

[ahmedneilhussain]

Thanks for rebasing, and sorry you had to give up waiting for me to do it and do it yourself! I had a few other bits and pieces I was entangled with for a couple of days...
I will rebase the test clean-up PR in a day or so hopefully to remove the bits that have been cherry-picked and then we can see which bits of the rest are controversial.

[mickaelistria]

Thanks for rebasing, and sorry you had to give up waiting for me to do it and do it yourself!

No problem.