Improvements to CS API "User Data" section (#2359)

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

changelogs/client_server/newsfragments/2359.clarification

@@ -0,0 +1 @@
+Clarify formats of string types.

content/client-server-api/_index.md

@@ -4214,13 +4214,13 @@ an automatic propagation event to occur, informing likely-interested
 parties of the new values. This change is conveyed using two separate
 mechanisms:
 
--   an `m.room.member` event (with a `join` membership) is sent to every
-    room the user is a member of, to update the `displayname` and
+-   an [`m.room.member`](#mroommember) event (with a `join` membership) is sent
+    to every room the user is a member of, to update the `displayname` and
     `avatar_url`.
--   an `m.presence` presence status update is sent, again containing the
-    new values of the `displayname` and `avatar_url` keys, in addition
-    to the required `presence` key containing the current presence state
-    of the user.
+-   an [`m.presence`](#mpresence) presence status update is sent, again
+    containing the new values of the `displayname` and `avatar_url` keys, in
+    addition to the required `presence` key containing the current presence
+    state of the user.
 
 Both of these should be done automatically by the homeserver when a user
 successfully changes their display name or avatar URL fields.

data/api/client-server/profile.yaml

@@ -46,6 +46,8 @@ paths:
           example: "@alice:example.com"
           schema:
             type: string
+            format: mx-user-id
+            pattern: "^@"
         - in: path
           name: keyName
           description: The name of the profile field to set. This MUST be either
@@ -158,6 +160,8 @@ paths:
           example: "@alice:example.com"
           schema:
             type: string
+            format: mx-user-id
+            pattern: "^@"
         - in: path
           name: keyName
           description: The name of the profile field to retrieve.
@@ -216,6 +220,8 @@ paths:
           example: "@alice:example.com"
           schema:
             type: string
+            format: mx-user-id
+            pattern: "^@"
         - in: path
           name: keyName
           description: The name of the profile field to delete.
@@ -286,6 +292,8 @@ paths:
           example: "@alice:example.com"
           schema:
             type: string
+            format: mx-user-id
+            pattern: "^@"
       responses:
         "200":
           description: The profile information for this user.

data/api/client-server/users.yaml

@@ -82,6 +82,8 @@ paths:
                           type: string
                           example: "@foo:bar.com"
                           description: The user's matrix user ID.
+                          format: mx-user-id
+                          pattern: "^@"
                         display_name:
                           type: string
                           example: Foo