Rename JSX files with proper .jsx extension (#23733)

app/javascript/mastodon/components/radio_button.jsx

@@ -0,0 +1,35 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import classNames from 'classnames';
+
+export default class RadioButton extends React.PureComponent {
+
+  static propTypes = {
+    value: PropTypes.string.isRequired,
+    checked: PropTypes.bool,
+    name: PropTypes.string.isRequired,
+    onChange: PropTypes.func.isRequired,
+    label: PropTypes.node.isRequired,
+  };
+
+  render () {
+    const { name, value, checked, onChange, label } = this.props;
+
+    return (
+      <label className='radio-button'>
+        <input
+          name={name}
+          type='radio'
+          value={value}
+          checked={checked}
+          onChange={onChange}
+        />
+
+        <span className={classNames('radio-button__input', { checked })} />
+
+        <span>{label}</span>
+      </label>
+    );
+  }
+
+}