src/sponsor: Fix button doing nothing.

Now it copies the address to the clipboard for convenience.

src/utils/ClipboardIcon.tsx

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2021-2022 The Pybricks Authors
+
+// Icon for indicating external links
+
+import { Icon } from '@blueprintjs/core';
+import React from 'react';
+
+import './clipboard.scss';
+
+const ClipboardIcon: React.VFC = (_props) => {
+    return (
+        <span className="pb-clipboard">
+            &nbsp;
+            <sup>
+                <Icon icon="duplicate" iconSize={12} />
+            </sup>
+        </span>
+    );
+};
+
+export default ClipboardIcon;

src/utils/clipboard.scss

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2021-2022 The Pybricks Authors
+
+@use '@blueprintjs/core/lib/scss/variables' as bp;
+
+span.pb-clipboard {
+    white-space: nowrap;
+}
+
+// override some button magic in case this is used in a button
+.#{bp.$ns}-button .pb-clipboard .#{bp.$ns}-icon:first-child:last-child {
+    margin: 0;
+}