message: clarify how lhs collapsed state is stored
diff: @@ -161,7 +161,7 @@ export default React.createClass({
  // If we're trying to just view a user ID (i.e. /user URL), this is it
  viewUserId: null,
  -
  + // this is persisted as mx_lhs_size, loaded in LoggedInView
  collapseLhs: false,
  collapsedRhs: window.localStorage.getItem("mx_rhs_collapsed") === "true",
  leftDisabled: false,
  