wrangling-genomics/02-quality-control: scp command needs clarity

[hoytpr]

At the time pscp.exe is invoked, the learner is in a terminal window where:
"(base) dcuser@ip-172-31-61-142:~$" can be the prompt. The lesson instructions are correct, but it needs more emphasis on using the dcuser@ec2-XXX-XXX-XXX-XXX rather than dcuser@ip-XXX-XXX-XXX-XXX. The instructions should make clear that .compute-1.amazonaws.com: must be part of the pscp or scp command. That would clear up most confusion.

A mention that the "ip address" uses dashes rather than periods. would clarify things as well.