feat(toggle): use vim.diagnostic.is_disabled when available (#2217)

* feat(toggle-diagnostics): change logic based on `vim.diagnostic.is_disabled`

After discussion in #2215, I thought maybe it would be beneficial if we
could change the logic of the `toggle-diagnostics` function based on if
the user has disabled diagnostics in his own configuration.

* feat(toggle-diagnostics): revert to `enable` instead of `status`

* fix(toggle): use vim.diagnostics enabled state when possible

---------

Co-authored-by: Folke Lemaitre <folke.lemaitre@gmail.com>

lua/lazyvim/util/toggle.lua

@@ -43,7 +43,13 @@ end
 
 local enabled = true
 function M.diagnostics()
+  -- if this Neovim version supports checking if diagnostics are enabled
+  -- then use that for the current state
+  if vim.diagnostic.is_disabled then
+    enabled = not vim.diagnostic.is_disabled()
+  end
   enabled = not enabled
+
   if enabled then
     vim.diagnostic.enable()
     Util.info("Enabled diagnostics", { title = "Diagnostics" })