declare various missing server capabilities

this should fix FluffyChat password resets, and
other possible client issues that expose features
based on server capabilities.

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/api/client_server/capabilities.rs

 use std::collections::BTreeMap;
 
 use ruma::api::client::discovery::get_capabilities::{
-	self, Capabilities, RoomVersionStability, RoomVersionsCapability,
+	self, Capabilities, ChangePasswordCapability, RoomVersionStability, RoomVersionsCapability, SetAvatarUrlCapability,
+	SetDisplayNameCapability, ThirdPartyIdChangesCapability,
 };
 
 use crate::{services, Result, Ruma};
 
-/// # `GET /_matrix/client/r0/capabilities`
+/// # `GET /_matrix/client/v3/capabilities`
 ///
 /// Get information on the supported feature set and other relevent capabilities
 /// of this server.
@@ -27,6 +28,23 @@ pub async fn get_capabilities_route(
 		available,
 	};
 
+	capabilities.change_password = ChangePasswordCapability {
+		enabled: true,
+	};
+
+	capabilities.set_avatar_url = SetAvatarUrlCapability {
+		enabled: true,
+	};
+
+	capabilities.set_displayname = SetDisplayNameCapability {
+		enabled: true,
+	};
+
+	// conduit does not implement 3PID stuff
+	capabilities.thirdparty_id_changes = ThirdPartyIdChangesCapability {
+		enabled: false,
+	};
+
 	Ok(get_capabilities::v3::Response {
 		capabilities,
 	})