Add `strip-root` flag to the `coverage` command
Add `strip-root` flag to the `coverage` command

Summary: This is a pretty standard flag for our commands, but somehow hadn't been added to `coverage` yet.

Reviewed By: dsainati1

Differential Revision: D13207069

fbshipit-source-id: 1d2318fae06f1486f67c47d208fb49729afe9d38

gabelevi/flow,popham/flow,samwgoldman/flow,gabelevi/flow,samwgoldman/flow,AgentME/flow,AgentME/flow,mroch/flow,facebook/flow,facebook/flow,samwgoldman/flow,gabelevi/flow,mroch/flow,mroch/flow,samwgoldman/flow,gabelevi/flow,AgentME/flow,samwgoldman/flow,mroch/flow,popham/flow,gabelevi/flow,popham/flow,popham/flow,popham/flow,popham/flow,AgentME/flow,popham/flow,mroch/flow,samwgoldman/flow,mroch/flow,AgentME/flow,facebook/flow,facebook/flow,gabelevi/flow,mroch/flow,facebook/flow,samwgoldman/flow,facebook/flow,facebook/flow,gabelevi/flow