fix(#2519): Diagnostics Not Updated When Tree Not Visible (#2597)

* fix(#2519): diagnostics overhaul

Signed-off-by: iusmac <iusico.maxim@libero.it>

* fix: Properly filter diagnostics from coc

Also, while we're at it, refactor the lsp function for consistency.
There should be no functional change, just cosmetic.

Signed-off-by: iusmac <iusico.maxim@libero.it>

* Assign diagnostic version per node to reduce overhead

Signed-off-by: iusmac <iusico.maxim@libero.it>

* Require renderer once

Signed-off-by: iusmac <iusico.maxim@libero.it>

* Revert "Require renderer once"

Causes circular requires after the previous commit.

This reverts commit 7413041630.

* Rename `buffer_severity_dict` to `BUFFER_SEVERITY`

Signed-off-by: iusmac <iusico.maxim@libero.it>

* Log diagnostics update properly

Signed-off-by: iusmac <iusico.maxim@libero.it>

* Implement error handling for coc.nvim

Signed-off-by: iusmac <iusico.maxim@libero.it>

* CI style fixes

Signed-off-by: iusmac <iusico.maxim@libero.it>

* Capture `Keyboard interrupt` when handling coc exceptions

Signed-off-by: iusmac <iusico.maxim@libero.it>

* add more doc

---------

Signed-off-by: iusmac <iusico.maxim@libero.it>
Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/renderer/components/diagnostics.lua

@@ -1,4 +1,5 @@
 local HL_POSITION = require("nvim-tree.enum").HL_POSITION
+local diagnostics = require "nvim-tree.diagnostics"
 
 local M = {
   HS_FILE = {},
@@ -17,10 +18,11 @@ function M.get_highlight(node)
   end
 
   local group
+  local diag_status = diagnostics.get_diag_status(node)
   if node.nodes then
-    group = M.HS_FOLDER[node.diag_status]
+    group = M.HS_FOLDER[diag_status and diag_status.value]
   else
-    group = M.HS_FILE[node.diag_status]
+    group = M.HS_FILE[diag_status and diag_status.value]
   end
 
   if group then
@@ -35,7 +37,8 @@ end
 ---@return HighlightedString|nil modified icon
 function M.get_icon(node)
   if node and M.config.diagnostics.enable and M.config.renderer.icons.show.diagnostics then
-    return M.ICON[node.diag_status]
+    local diag_status = diagnostics.get_diag_status(node)
+    return M.ICON[diag_status and diag_status.value]
   end
 end