message: Improve createAccountDataAction docs
diff: @@ -19,7 +19,8 @@ import dis from '../dispatcher';
  // TODO: migrate from sync_state to MatrixActions.sync so that more js-sdk events
  // become dispatches in the same place.
  /**
  - * Create a MatrixActions.sync action that represents a MatrixClient `sync` event.
  + * Create a MatrixActions.sync action that represents a MatrixClient `sync` event,
  + * each parameter mapping to a key-value in the action.
  *
  * @param {MatrixClient} matrixClient the matrix client
  * @param {string} state the current sync state.
  @@ -35,13 +36,22 @@ function createSyncAction(matrixClient, state, prevState) {
  };
  }
  +/**
  + * @typedef AccountDataAction
  + * @type {Object}
  + * @property {string} action 'MatrixActions.accountData'.
  + * @property {MatrixEvent} event the MatrixEvent that triggered the dispatch.
  + * @property {string} event_type the type of the MatrixEvent, e.g. "m.direct".
  + * @property {Object} event_content the content of the MatrixEvent.
  + */
  +
  /**
  * Create a MatrixActions.accountData action that represents a MatrixClient `accountData`
  * matrix event.
  *
  * @param {MatrixClient} matrixClient the matrix client.
  * @param {MatrixEvent} accountDataEvent the account data event.
  - * @returns {Object} an action of type MatrixActions.accountData.
  + * @returns {AccountDataAction} an action of type MatrixActions.accountData.
  */
  function createAccountDataAction(matrixClient, accountDataEvent) {
  return {
  