message: fix leftArrowIcon docs
diff: @@ -104,7 +104,7 @@ cancelLabel | string | 'Cancel' | The label for the cancel button
  clearLabel | string | 'Clear' | The label for the clear button
  labelFunc | func | null | Allow to specify dynamic label for text field `labelFunc(date, invalidLabel)`. Note, that `date` equals `null` after picker is cleared.
  renderDay | func | null | Allow to specify custom renderer for day `renderDay(date, selectedDate, dayInCurrentMonth)`
  -leftArrowIcon | react node | `<Icon>keyboard_arrow_left</Icoln>` Left arrow icon
  +leftArrowIcon | react node | `<Icon>keyboard_arrow_left</Icon>`| Left arrow icon
  rightArrowIcon | react node | `<Icon>keyboard_arrow_right</Icon>`| Right arrow icon
  shouldDisableDate | (date: Moment) => boolean | () => false | Allow to disable custom date in calendar
  keyboard | boolean | false | Allow to manual input date to the text field
  @@ -159,7 +159,7 @@ cancelLabel | string | 'Cancel' | The label for the cancel button
  clearLabel | string | 'Clear' | The label for the clear button
  labelFunc | func | null | Allow to specify dynamic label for text field `labelFunc(date, invalidLabel)`. Note, that `date` equals `null` after picker is cleared.
  renderDay | func | null | Allow to specify custom renderer for day `renderDay(date, selectedDate, dayInCurrentMonth)`
  -leftArrowIcon | react node | `<Icon>keyboard_arrow_left</Icoln>` Left arrow icon
  +leftArrowIcon | react node | `<Icon>keyboard_arrow_left</Icon>`| Left arrow icon
  rightArrowIcon | react node | `<Icon>keyboard_arrow_right</Icon>`| Right arrow icon
  dateRangeIcon | react node | `<Icon>date_range</Icon>`| Date tab icon
  timeIcon | react node | `<Icon>access_time</Icon>`| Time tab icon
  