doc/install.html: address comments from review of previous edit
doc/install.html: address comments from review of previous edit

Point out that one can just run the commands now; it's not necessary
to log out first.

Change-Id: I48d0cc0273d97ba54ce59b3a3bbcae0b5af9aaef
Reviewed-on: https://go-review.googlesource.com/106195
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/go,CAFxX/go,cloudflare/go,akutz/go,CAFxX/go,CAFxX/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,akutz/go,golang/go,nawawi/go,josharian/go,nawawi/go,josharian/go,nawawi/go,golang/go,CAFxX/go,cloudflare/go,akutz/go,cloudflare/go,golang/go,josharian/go,golang/go,cloudflare/go,josharian/go,nawawi/go,akutz/go,golang/go,cloudflare/go,josharian/go,golang/go,cloudflare/go,CAFxX/go,akutz/go,cloudflare/go,josharian/go,CAFxX/go,akutz/go,nawawi/go,josharian/go,josharian/go,nawawi/go,golang/go,akutz/go,akutz/go