message: fix fn call, fixes usage of SlashCommands
diff: @@ -988,7 +988,7 @@ export default class MessageComposerInput extends React.Component {
  firstGrandChild.text[0] === '/')
  {
  commandText = this.plainWithIdPills.serialize(editorState);
  - cmd = SlashCommands.processInput(this.props.room.roomId, commandText);
  + cmd = processCommandInput(this.props.room.roomId, commandText);
  }
  if (cmd) {
  