fixed SUMOEng with open instead of import for the Extension module

examples/SUMO/RGLExt/DictLangEng.gf

@@ -1,8 +1,8 @@
 --# -path=.:../../../lib/src/abstract:../../../lib/src/english:../../../lib/src/common
 
 concrete DictLangEng of DictLang = 
-  GrammarEng,
-  ExtensionEng ** {
+  GrammarEng
+  ** open ExtensionEng in {
 
 flags  unlexer = text ; lexer = text ;