Merge branch 'describe-todoactionenum' into 'master'

Describe TodoActionEnum

See merge request gitlab-org/gitlab!55030

app/graphql/types/todo_action_enum.rb

@@ -2,12 +2,14 @@
 
 module Types
   class TodoActionEnum < BaseEnum
-    value 'assigned', value: 1
-    value 'mentioned', value: 2
-    value 'build_failed', value: 3
-    value 'marked', value: 4
-    value 'approval_required', value: 5
-    value 'unmergeable', value: 6
-    value 'directly_addressed', value: 7
+    value 'assigned', value: 1, description: 'User was assigned.'
+    value 'mentioned', value: 2, description: 'User was mentioned.'
+    value 'build_failed', value: 3, description: 'Build triggered by the user failed.'
+    value 'marked', value: 4, description: 'User added a TODO.'
+    value 'approval_required', value: 5, description: 'User was set as an approver.'
+    value 'unmergeable', value: 6, description: 'Merge request authored by the user could not be merged.'
+    value 'directly_addressed', value: 7, description: 'User was directly addressed.'
+    value 'merge_train_removed', value: 8, description: 'Merge request authored by the user was removed from the merge train.'
+    value 'review_requested', value: 9, description: 'Review was requested from the user.'
   end
 end

doc/api/graphql/reference/index.md

@@ -5858,13 +5858,15 @@ State of a test report.
 
 | Value | Description |
 | ----- | ----------- |
-| `approval_required` |  |
-| `assigned` |  |
-| `build_failed` |  |
-| `directly_addressed` |  |
-| `marked` |  |
-| `mentioned` |  |
-| `unmergeable` |  |
+| `approval_required` | User was set as an approver. |
+| `assigned` | User was assigned. |
+| `build_failed` | Build triggered by the user failed. |
+| `directly_addressed` | User was directly addressed. |
+| `marked` | User added a TODO. |
+| `mentioned` | User was mentioned. |
+| `merge_train_removed` | Merge request authored by the user was removed from the merge train. |
+| `review_requested` | Review was requested from the user. |
+| `unmergeable` | Merge request authored by the user could not be merged. |
 
 ### TodoStateEnum