Remaining DD keymap_extras migration (#19110)

* Parse headers to data

* Regen headers from data

util/lang_gen.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+for lang in $(find data/constants/keycodes/extras/ -type f -printf "%f\n" | sed "s/keycodes_//g" | sed "s/_[0-9].*//"); do
+  data=$(qmk generate-keycode-extras --version latest --lang $lang)
+  if [ "$?" == "0" ]; then
+    echo "$data" > quantum/keymap_extras/keymap_$lang.h
+  fi
+done