Tags can never include a comma

And no, I don't want "\," to be legal in our tag, either. Way too much
pain for way too little gain.

Fixes #560

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/groupedlineedit.cpp

@@ -86,7 +86,7 @@ void GroupedLineEdit::addBlock(int start, int end)
 	Private::Block block;
 	block.start = start;
 	block.end = end;
-	block.text = text().mid(start, end - start + 1).trimmed();
+	block.text = text().mid(start, end - start + 1).remove(',').trimmed();
 	d->blocks.append(block);
 	viewport()->update();
 }