wxGUI: fix SyntaxError from https://trac.osgeo.org/grass/changeset/57913

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@57938 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/lmgr/frame.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """!
 @package lmgr::frame