onboarding: Update Welcome Bot.
onboarding: Update Welcome Bot.

The most important thing is linking to the new user guide.

eeshangarg/zulip,andersk/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,eeshangarg/zulip,kou/zulip,zulip/zulip,andersk/zulip,rht/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,rht/zulip,zulip/zulip,andersk/zulip,rht/zulip,rht/zulip,zulip/zulip,rht/zulip,andersk/zulip,zulip/zulip,kou/zulip,kou/zulip,andersk/zulip,zulip/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,kou/zulip,eeshangarg/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,rht/zulip