message: improve l10n docs
  prevents issues like
diff: @@ -136,6 +136,14 @@ rightArrowIcon | react node, string | 'keyboard_arrow_right'| Right arrow icon
  dateRangeIcon | react node, string | 'date_range'| Date tab icon
  timeIcon | react node, string | 'access_time'| Time tab icon
  +### l10n
  +For l10n texts we're currently relying on moment which is stateful. To change the locale you have to import your langauge specific files an change the locale manually via `moment.locale(language)`.
  +```
  +import moment from 'moment'
  +import 'moment/locale/fr';
  +
  +moment.locale('fr')
  +```
  ### Known Issues
  1. 24 hour displaying for timepicker (now supporting only am/pm)
  