more correct error message

--- a/src/Tools/Code/code_scala.ML	Wed Apr 25 09:04:25 2018 +0000
+++ b/src/Tools/Code/code_scala.ML	Wed Apr 25 09:04:26 2018 +0000
@@ -36,7 +36,7 @@
           if i < 32 orelse i > 126
           then chr i
           else if i >= 128
-          then error "non-ASCII byte in Haskell string literal"
+          then error "non-ASCII byte in Scala string literal"
           else c
         end
   in quote o translate_string char end;