use gift icon for tips

src/renderer/constants/icons.js

@@ -27,3 +27,4 @@ export const UNLOCK = 'Unlock';
 export const CHECK_SIMPLE = 'Check';
 export const GLOBE = 'Globe';
 export const EXTERNAL_LINK = 'ExternalLink';
+export const GIFT = 'Gift';

src/renderer/page/file/view.jsx

@@ -200,7 +200,7 @@ class FilePage extends React.Component<Props> {
                     {!claimIsMine && (
                       <Button
                         button="alt"
-                        icon="Send"
+                        icon={icons.GIFT}
                         label={__('Enjoy this? Send a tip')}
                         onClick={() => openModal({ id: MODALS.SEND_TIP }, { uri })}
                       />