readme: add doc links

Author: tulir

README.md

@@ -2,16 +2,13 @@
 A Matrix-Zulip puppeting bridge.
 
 ## Documentation
-None yet.
-<!--
 All setup and usage instructions are located on [docs.mau.fi]. Some quick links:
 
 [docs.mau.fi]: https://docs.mau.fi/bridges/go/zulip/index.html
 
 * [Bridge setup](https://docs.mau.fi/bridges/go/setup.html?bridge=zulip)
   (or [with Docker](https://docs.mau.fi/bridges/general/docker-setup.html?bridge=zulip))
 * Basic usage: [Authentication](https://docs.mau.fi/bridges/go/zulip/authentication.html)
--->
 
 ### Features & Roadmap
 [ROADMAP.md](ROADMAP.md) contains a general overview of what is supported by the bridge.