fix(treesitter): highlight group for EditQuery captures #36265

fix(treesitter): more distinctive highlight for EditQuery captures

Problem: EditQuery shows captures in the source buffer using the Title
highlight group, which could be too similar to Normal.

Solution: Use a virtual text diagnostic highlight group: they are
displayed in a similar manner to the query captures so we can assume
that the color scheme should have appropriate styling applied to make
them visible.

runtime/lua/vim/treesitter/dev.lua

@@ -608,7 +608,7 @@ local function update_editor_highlights(query_win, base_win, lang)
           end_col = end_col,
           hl_group = 'Visual',
           virt_text = {
-            { capture_name, 'Title' },
+            { capture_name, 'DiagnosticVirtualTextHint' },
           },
         })
       end