Fix highlighting when pasting multiple lines

The solution was to do the highlighting for each change independently.
The problem is that the match trees of different changes overlap, which
can cause a node to be considered its own child when assembling the
final match tree.

lua/rainbow-delimiters/strategy/global2.lua

@@ -57,11 +57,11 @@ local function update_range(bufnr, changes, tree, lang)
 	if not query then return end
 
 	---Temporary stack of partial match trees; used to build the final match trees
-	local match_trees = Stack.new()
 	local root_node = tree:root()
 
 	-- Build the match tree
 	for _, change in ipairs(changes) do
+		local match_trees = Stack.new()
 		local start_row, end_row = change[1], change[3] + 1
 		lib.clear_namespace(bufnr, lang, start_row, end_row)
 
@@ -79,10 +79,9 @@ local function update_range(bufnr, changes, tree, lang)
 			end
 			match_trees:push(this)
 		end
-	end
-
-	for _, match_tree in match_trees:iter() do
-		MatchTree.highlight(match_tree, bufnr, lang, 1)
+		for _, match_tree in match_trees:iter() do
+			MatchTree.highlight(match_tree, bufnr, lang, 1)
+		end
 	end
 end