Improve silence datetime display.
Improve silence datetime display.

brancz/alertmanager,Aloomaio/alertmanager,pdf/alertmanager,novilabs/alertmanager,novilabs/alertmanager,pdf/alertmanager,brunoqc/alertmanager,tbouvet/alertmanager,Aloomaio/alertmanager,pdf/alertmanager,tyrken/alertmanager,Kellel/alertmanager,ericgerling/alertmanager,joehandzik/alertmanager,MonsantoCo/alertmanager,sarathsp06/alertmanager,GoogleCloudPlatform/alertmanager,pdf/alertmanager,brancz/alertmanager,brancz/alertmanager,Kellel/alertmanager,brancz/alertmanager,tyrken/alertmanager,Kellel/alertmanager,GoogleCloudPlatform/alertmanager,GoogleCloudPlatform/alertmanager,tinytub/alertmanager,MonsantoCo/alertmanager,ericgerling/alertmanager,brunoqc/alertmanager,ericgerling/alertmanager,tinytub/alertmanager,novilabs/alertmanager,sarathsp06/alertmanager,tbouvet/alertmanager,tyrken/alertmanager,tbouvet/alertmanager,brunoqc/alertmanager,prometheus/alertmanager,sarathsp06/alertmanager,novilabs/alertmanager,Aloomaio/alertmanager,GoogleCloudPlatform/alertmanager,prometheus/alertmanager,joehandzik/alertmanager,MonsantoCo/alertmanager,prometheus/alertmanager,MonsantoCo/alertmanager,joehandzik/alertmanager,tinytub/alertmanager,brunoqc/alertmanager,tyrken/alertmanager,prometheus/alertmanager