dateTimeLabelFormats add list support

[ytian]

https://api.highcharts.com/highstock/plotOptions.series.dataGrouping

dateTimeLabelFormats: object
Datetime formats for the header of the tooltip in a stock chart. The format can vary within a chart depending on the currently selected time range and the current data grouping.

The default formats are:

{
millisecond: [
'%A, %b %e, %H:%M:%S.%L', '%A, %b %e, %H:%M:%S.%L', '-%H:%M:%S.%L'
],
second: ['%A, %b %e, %H:%M:%S', '%A, %b %e, %H:%M:%S', '-%H:%M:%S'],
minute: ['%A, %b %e, %H:%M', '%A, %b %e, %H:%M', '-%H:%M'],
hour: ['%A, %b %e, %H:%M', '%A, %b %e, %H:%M', '-%H:%M'],
day: ['%A, %b %e, %Y', '%A, %b %e', '-%A, %b %e, %Y'],
week: ['Week from %A, %b %e, %Y', '%A, %b %e', '-%A, %b %e, %Y'],
month: ['%B %Y', '%B', '-%B %Y'],
year: ['%Y', '%Y', '-%Y']
}