add utf8.escape_xml and alias - string.escape_xml

src/logic/scripting/lua/libs/libutf8.cpp

@@ -88,6 +88,11 @@ static int l_escape(lua::State* L) {
     return lua::pushstring(L, util::escape(string));
 }
 
+static int l_escape_xml(lua::State* L) {
+    auto string = lua::require_lstring(L, 1);
+    return lua::pushstring(L, util::escape_xml(string));
+}
+
 const luaL_Reg utf8lib[] = {
     {"tobytes", lua::wrap<l_tobytes>},
     {"tostring", lua::wrap<l_tostring>},
@@ -98,5 +103,6 @@ const luaL_Reg utf8lib[] = {
     {"lower", lua::wrap<l_lower>},
     {"encode", lua::wrap<l_encode>},
     {"escape", lua::wrap<l_escape>},
+    {"escape_xml", lua::wrap<l_escape_xml>},
     {nullptr, nullptr}
 };