Update API-Mastodon.md Fixes #13914

- removed unsupported clients (information is no longer accurate) and simplified Clients section
- new API Endpoints were added in https://github.com/friendica/friendica/pull/14007

doc/API-Mastodon.md

@@ -11,21 +11,7 @@ Authentication is the same as described in [Using the APIs](help/api#Authenticat
 
 ## Clients
 
-### Supported apps
+Please find a list of supported apps at [FAQ](help/FAQ#clients).
-
-For supported apps please have a look at the [FAQ](help/FAQ#clients)
-
-### Unsupported apps
-
-#### Android
-
-- [Fedilab](https://framagit.org/tom79/fedilab) Automatically uses the legacy API, see issue: https://framagit.org/tom79/fedilab/-/issues/520
-- [Mammut](https://github.com/jamiesanson/Mammut) There are problems with the token request, see issue https://github.com/jamiesanson/Mammut/issues/19
-
-#### iOS
-
-- [Mast](https://github.com/Beesitech/Mast) Doesn't accept the entered instance name. Claims that it is invalid (Message is: "Not a valid instance (may be closed or dead)")
-- [Toot!](https://apps.apple.com/app/toot/id1229021451)
 
 ## Entities