Mention that the device must be plugged via USB before configuring
TCP/IP connections.
It wasn't obvious that the device should be first plugged before running
scrcpy wirelessly, especially to those who aren't very familiar with
adb.
Note from committer: add this new step with index 0 to make the diff
readable, the next commit will renumber all the steps.
PR #1303 <https://github.com/Genymobile/scrcpy/pull/1303>
Signed-off-by: Romain Vimont <rom@rom1v.com>
