http/httpproxy: remove comment on https proxy precedance
http/httpproxy: remove comment on https proxy precedance

For golang/go#40909
For golang/go#54890

Change-Id: I1de1803f8fd00f54290404a8760d9f704ff766c3
Reviewed-on: https://go-review.googlesource.com/c/net/+/428795
Auto-Submit: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
Run-TryBot: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
Reviewed-by: Damien Neil <7e091e9a80da888fcd7836fd3c6b7b85f4677c12@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>

golang/net