Fix title name

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

content/client-server-api/_index.md

@@ -1456,12 +1456,12 @@ forwarded to the login endpoint during the login process. For example:
 
     GET /_matrix/static/client/login/?device_id=GHTYAJCE
 
-### Account registration
+### Account registration and management
+
+#### Account Registration
 
 {{% http-api spec="client-server" api="registration" %}}
 
-### Account management
-
 #### Password management
 
 {{% boxes/warning %}}