Mutates the original moment by setting it to the end of a unit of time.
This is the same as
moment#startOf, only instead of setting to the start of a unit of time, it sets to the end of a unit of time.
moment().endOf("year"); // set the moment to 12-31 23:59:59.999 this year
As of version 2.0.0,
moment#endOf('week') was added in version 2.0.0.
As of version 2.1.0,
moment#endOf('week') uses the locale aware week start day.