feat(group): document more error responses (#303)

Document some more error responses for group endpoints.

openapi/components/paths/groups.yaml

@@ -438,9 +438,11 @@ paths:
         '200':
           description: OK
         '400':
-          description: User <displayName> is already invited
+          $ref: ../responses/groups/GroupInviteBadRequestError.yaml
         '401':
           $ref: ../responses/MissingCredentialsError.yaml
+        '403':
+          $ref: ../responses/groups/GroupInviteForbiddenError.yaml
         '404':
           $ref: ../responses/groups/GroupNotFoundError.yaml
       security:
@@ -652,6 +654,8 @@ paths:
       responses:
         '200':
           $ref: ../responses/groups/GroupMemberListResponse.yaml
+        '400':
+          $ref: ../responses/groups/GroupJoinRequestResponseBadRequestError.yaml
         '403':
           $ref: ../responses/groups/GroupNotMemberError.yaml
         '404':

openapi/components/responses/groups/GroupInviteBadRequestError.yaml

@@ -0,0 +1,16 @@
+description: Bad request error response when creating a group invite.
+content:
+  application/json:
+    schema:
+      $ref: ../../schemas/Error.yaml
+    examples:
+      Group Member Already Exists:
+        value:
+          error:
+            message: User <displayName> is already a member of this group.
+            status_code: 400
+      User Already Invited:
+        value:
+          error:
+            message: User <displayName> is already invited.
+            status_code: 400

openapi/components/responses/groups/GroupInviteForbiddenError.yaml

@@ -0,0 +1,11 @@
+description: Forbidden error response when creating a group invite.
+content:
+  application/json:
+    schema:
+      $ref: ../../schemas/Error.yaml
+    examples:
+      Forbidden to Invite User:
+        value:
+          error:
+            message: You can't invite that user․
+            status_code: 403

openapi/components/responses/groups/GroupJoinRequestResponseBadRequestError.yaml

@@ -0,0 +1,11 @@
+description: Bad request error response when responding to a group join request
+content:
+  application/json:
+    schema:
+      $ref: ../../schemas/Error.yaml
+    examples:
+      User Join Request Not Exist:
+        value:
+          error:
+            message: You can't accept a join request for a user who hasn't requested to join․
+            status_code: 400