feat: resupport force stop language server

[superatomic]

Reintroduces behavior added in #2294. See #4136 for discussion.

Differences from the old implementation:

• Uses :LspStop! instead of :LspStop ++force. If this is an undesirable change, I can implement it the original way.
• Supports the same behavior for :LspRestart.

[justinmk]

enable(false) already calls :stop(): https://github.com/neovim/neovim/blob/b67eff38fe19876ab228007897224ec04b58aa40/runtime/lua/vim/lsp.lua#L590-L591

oh, but I see this PR adds a true arg to "force" it.

but you can already get "force" behavior by calling LspStop twice?

--- By default, it will just request the server to shutdown without force. If
--- you request to stop a client which has previously been requested to
--- shutdown, it will automatically escalate and force shutdown.

If that's not good enough, I suggest sending a PR to Nvim core (and we can backport it to Nvim 0.11) which will automatically "escalate" after X seconds, similar to what we already do on Nvim exit.

[superatomic]

It is true that you can call LspStop twice to achieve this force behavior. The issue is that some servers require being forced-stopped, and having to run :LspStop twice every single time in these instances can be annoying.

I'll take a look at adding escalation behavior to neovim core.

[justinmk]

good idea 👍

[justinmk]

The code here is actually a nice improvement, and the bang variant is quite reasonable. So let's merge this.

I'll take a look at adding escalation behavior to neovim core.

That will be appreciated, it's the standard pattern that all such "teardown"/"stop" features should follow.