feat(treesitter): allow capture text to be transformed

Co-authored-by: Lewis Russell <lewis6991@gmail.com>

runtime/lua/vim/treesitter/query.lua

@@ -452,6 +452,21 @@ local directive_handlers = {
       metadata[capture_id].range = range
     end
   end,
+
+  -- Transform the content of the node
+  -- Example: (#gsub! @_node ".*%.(.*)" "%1")
+  ['gsub!'] = function(match, _, bufnr, pred, metadata)
+    assert(#pred == 4)
+
+    local id = pred[2]
+    local node = match[id]
+    local text = M.get_node_text(node, bufnr, { metadata = metadata[id] }) or ''
+
+    if not metadata[id] then
+      metadata[id] = {}
+    end
+    metadata[id].text = text:gsub(pred[3], pred[4])
+  end,
 }
 
 --- Adds a new predicate to be used in queries