Removed unneeded newlines from parsed comments

Newlines from comments separated by lines are retained when comments
are appended, so adding a newline between separate comments for a
node is not needed.

src/lib_json/json_reader.cpp

@@ -358,8 +358,6 @@ Reader::addComment(Location begin, Location end, CommentPlacement placement) {
     assert(lastValue_ != 0);
     lastValue_->setComment(std::string(begin, end), placement);
   } else {
-    if (!commentsBefore_.empty())
-      commentsBefore_ += "\n";
     commentsBefore_ += std::string(begin, end);
   }
 }