Add copyright header to popover.lua

popover.lua

@@ -1,3 +1,22 @@
+--
+-- Flow: Popovers
+--
+-- Copyright © 2022-2025 by luk3yx
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Lesser General Public License as published by
+-- the Free Software Foundation, either version 2.1 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Lesser General Public License for more details.
+--
+-- You should have received a copy of the GNU Lesser General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
 local align_types, apply_padding, get_and_fill_in_sizes, expand = ...
 
 local function handle_popovers(box, node)