Update WPR instructions to match new mod changes
Update WPR instructions to match new mod changes

Reletive paths and extra info should make this more useful for users.

Bug: chromium:1032253
Change-Id: I987140a054bb01742c25168539cf61c3302c5bdf
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/2415399
Reviewed-by: John Chen <334fbfbb4df7c78f091ea1b77c69ca6ac731a3f3@chromium.org>
Commit-Queue: Ian Struiksma <bcfd9536a4646851deabd7f4a8817546cbfc628b@google.com>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult