fix: preserve diagnostics across perspective switches

[LemonBreezes]

This patch fixes lsp-treemacs-sync-mode in Doom Emacs. Without this patch, lsp-treemacs-sync-mode completely breaks when persp-mode is enabled.

[LemonBreezes]

Hello jcs090218. Would you please review this change and #172? #172 can be refactored with mapconcat but is otherwise good. These changes make some pretty important fixes.

[LemonBreezes]

Also, let's do #166 as well. Local variables and constants might seem useful to show on the surface but when you actually show them, there are so many it's not useful.

[jcs090218]

I don't use persp-mode. Can you explain why it breaks persp-mode? 🤔

Thanks!

[LemonBreezes]

I don't use persp-mode. Can you explain why it breaks persp-mode? 🤔

Thanks!

What is happening is that when we are switching persps, we are turning off those servers so when we switch back and re-add the folders, they have no connections so the errors list disappears when switching out of and back into a workspace. This is a solution to work around that: remove them but do not shut down the servers.

[LemonBreezes]

@yyoncho Hello. You are familiar with LSP. Would you please take a look?

[LemonBreezes]

@jcs090218 Hey, any update on merging this?