Debounce LSP Diagnostics in INSERT mode.

[stephenmartindale]

I must say that I am absolutely loving the new diagnostics features in Helix 25.01 – I'd argue that they're worth switching to Helix for, alone.

However, when one enters insert mode and starts typing, Helix doesn't appear to do any kind of debouncing and the result is a very jarring and shaky experience with diagnostics flashing up on the screen because keyboard entry enters characters and not whole syntax tokens.

Helix is a modal editor. It has an INSERT mode which gives an unambiguous signal that the user intends to make code changes. That's ideal to know precisely when LSP queries may be neatly debounced to calm the user's experience without making the editor feel tardy!

Please add a simple timeout for these LSP diagnostics, for keyboard entry in INSERT mode.

Making it configurable would be ideal but I'd guess a timeout of circa 300ms would be good – that's what my venerable Neovim configuration used to cull the key help popups.

It should be long enough to let a common user type a known keyword or type name, like let or string, completely, before querying the LSP instead of querying the lsp 3 or 6 times (respectively) and potentially flashing up an error (n-1) times for each!