fixup! Add support for rendering custom emojis in reactions

Signed-off-by: Sumner Evans <me@sumnerevans.com>

Author: sumnerevans

src/components/views/messages/ReactionsRowButton.tsx

@@ -134,6 +134,7 @@ export default class ReactionsRowButton extends React.PureComponent<IProps, ISta
                 {content.startsWith("mxc://") ? (
                     <img
                         className="mx_ReactionsRowButton_content"
+                        alt={content}
                         src={MatrixClientPeg.get().mxcUrlToHttp(content)}
                         width="16"
                         height="16"