message: Fix regression where info at position was not showing updates.
  I thought I could remove MessagesContext.Provider but I couldn't.
diff: @@ -89,7 +89,7 @@ function Main(props: {}) {
  }
  const allMessages = processMessages(messages, null);
  return <div className="ma2">
  - <ConfigContext.Provider value={config}>
  + <ConfigContext.Provider value={config}><MessagesContext.Provider value={messages}>
  {pinnedLocs.map(({loc, paused},i) => {
  const isCursor = locationEq(loc,curLoc.loc);
  const key = isCursor ? 'cursor' : locationKey(loc);
  @@ -101,7 +101,7 @@ function Main(props: {}) {
  <Messages messages={allMessages}/>
  </div>
  </details>
  - </ConfigContext.Provider>
  + </MessagesContext.Provider></ConfigContext.Provider>
  </div>
  }
  