Remove reference to ExtendTur which isn't present in the repo

src/turkish/AllTur.gf

@@ -1,6 +1,6 @@
 --# -path=.:../abstract:../common:../prelude
 
 concrete AllTur of AllTurAbs = 
-  LangTur,
-  ExtendTur
+  LangTur
+--  ,ExtendTur
   ** {} ;