Start to split out initialization and registration (#21787)

Still TODO:

* [x] Factor out `start_language_server` so we can call it on register
(instead of on detect language)
* [x] Only call register in singleton editors (or when
editing/go-to-definition etc. in a multibuffer?)
* [x] Refcount on register so we can unregister when no buffer remain
* [ ] (maybe) Stop language servers that are no longer needed after some
time

Release Notes:

- Fixed language servers starting when doing project search
- Fixed high CPU usage when ignoring warnings in the diagnostics view

---------

Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>
Co-authored-by: Cole <cole@zed.dev>

crates/assistant/src/assistant_panel.rs

@@ -5113,9 +5113,11 @@ fn make_lsp_adapter_delegate(
             return Ok(None::<Arc<dyn LspAdapterDelegate>>);
         };
         let http_client = project.client().http_client().clone();
-        project.lsp_store().update(cx, |lsp_store, cx| {
+        project.lsp_store().update(cx, |_, cx| {
             Ok(Some(LocalLspAdapterDelegate::new(
-                lsp_store,
+                project.languages().clone(),
+                project.environment(),
+                cx.weak_model(),
                 &worktree,
                 http_client,
                 project.fs().clone(),