fix markdown header syntax

docs/modules.md

@@ -1,24 +1,26 @@
+# Modules
+
 Like any Django system, kepi consists of a set of interacting modules.
 (Django calls these "apps", confusingly.) In theory, it should be
 possible to pull any of these modules out and use them in another project.
 
-== trilby_api ==
+## trilby_api
 
 Trilby implements [the Mastodon protocol](https://docs.joinmastodon.org/).
 It also holds the microblogging data-- user details, statuses, and so on.
 
-== bowler_pub ==
+## bowler_pub
 
 Bowler implements [the ActivityPub protocol](https://www.w3.org/TR/activitypub/).
 It receives incoming messages from other servers, validates them, and acts upon them.
 It's also responsible for fetching ActivityPub objects from other servers.
 
-== sombrero_sendpub ==
+## sombrero_sendpub
 
 Sombrero delivers messages to other ActivityPub servers.
 As part of this, it handles webfinger lookup.
 
-== tophat_ui ==
+## tophat_ui
 
 Tophat handles the web UI. At present, we don't have much of a web interface:
 Tophat produces only the root page. Eventually it will produce HTML pages,
@@ -29,7 +31,7 @@ It should also have a general web UI as an alternative to using a client program
 Given the fact that we implement the Mastodon protocol,
 it's possible we can just merge in Mastodon's entire web UI.
 
-== busby_1st ==
+## busby_1st
 
 Busby handles incoming webfinger lookups, as well as the other `.well-known` services
 such as `host-meta`.