add generic caption typography component (#9283)

src/components/views/typography/Caption.tsx

@@ -0,0 +1,27 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React, { HTMLAttributes } from 'react';
+
+interface Props extends Omit<HTMLAttributes<HTMLSpanElement>, 'className'> {
+    children: React.ReactNode;
+}
+
+export const Caption: React.FC<Props> = ({ children, ...rest }) => {
+    return <span className='mx_Caption' {...rest}>
+        { children }
+    </span>;
+};