Add linefeeds to error messages allowing for consistant handling.

* HTMLtree.c xmlsave.c: Add linefeeds to error messages allowing
  for consistant handling.
diff --git a/HTMLtree.c b/HTMLtree.c
index d73024a..c1e5a0a 100644
--- a/HTMLtree.c
+++ b/HTMLtree.c
@@ -348,19 +348,19 @@
 
     switch(code) {
         case XML_SAVE_NOT_UTF8:
-	    msg = "string is not in UTF-8";
+	    msg = "string is not in UTF-8\n";
 	    break;
 	case XML_SAVE_CHAR_INVALID:
-	    msg = "invalid character value";
+	    msg = "invalid character value\n";
 	    break;
 	case XML_SAVE_UNKNOWN_ENCODING:
-	    msg = "unknown encoding %s";
+	    msg = "unknown encoding %s\n";
 	    break;
 	case XML_SAVE_NO_DOCTYPE:
-	    msg = "HTML has no DOCTYPE";
+	    msg = "HTML has no DOCTYPE\n";
 	    break;
 	default:
-	    msg = "unexpected error number";
+	    msg = "unexpected error number\n";
     }
     __xmlSimpleError(XML_FROM_OUTPUT, code, node, msg, extra);
 }