tweak titles

tsa/howto/conference.mdwn

@@ -109,7 +109,7 @@ The actualy prices quoted from Hetzner but virtual servers would
 probably be hosted in our infrastructure which might or might not
 incur additional costs.
 
-Cost estimate summary:
+### Summary
 
 | Platform        | One time  | Monthly        | Other                               |
 | --------        | --------  | -------        | ----------------------------------- |
@@ -117,7 +117,7 @@ Cost estimate summary:
 | Jitsi           | 74 hours  | €54 + 10 hours |                                     |
 | Big Blue Button | 156 hours | €54 + 8 hours  |                                     |
 
-Important caveats:
+### Caveats
 
  1. **Mumble is harder to use** and has proven to absolutely **require
     a headset** to function reliably