help: Clarify guest users on public streams.
help: Clarify guest users on public streams.

The previous language was unclear that we were talking about how the
features interacted, but the users.

zulip/zulip,kou/zulip,rht/zulip,rht/zulip,andersk/zulip,punchagan/zulip,andersk/zulip,andersk/zulip,hackerkid/zulip,hackerkid/zulip,hackerkid/zulip,eeshangarg/zulip,andersk/zulip,punchagan/zulip,eeshangarg/zulip,zulip/zulip,eeshangarg/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,hackerkid/zulip,zulip/zulip,punchagan/zulip,rht/zulip,punchagan/zulip,hackerkid/zulip,eeshangarg/zulip,zulip/zulip,punchagan/zulip,hackerkid/zulip,hackerkid/zulip,kou/zulip,kou/zulip,rht/zulip,andersk/zulip,kou/zulip,kou/zulip,rht/zulip,andersk/zulip,rht/zulip,zulip/zulip,punchagan/zulip,rht/zulip,kou/zulip,zulip/zulip,punchagan/zulip