Clarify milestone_id scope for API operations on Issuables

doc/api/issues.md

@@ -467,7 +467,7 @@ POST /projects/:id/issues
 | `description`                             | string  | no       | The description of an issue  |
 | `confidential`                            | boolean | no       | Set an issue to be confidential. Default is `false`.  |
 | `assignee_ids`                            | Array[integer] | no       | The ID of the users to assign issue |
-| `milestone_id`                            | integer | no       | The ID of a milestone to assign issue  |
+| `milestone_id`                            | integer | no       | The global ID of a milestone to assign issue  |
 | `labels`                                  | string  | no       | Comma-separated label names for an issue  |
 | `created_at`                              | string  | no       | Date time string, ISO 8601 formatted, e.g. `2016-03-11T03:45:40Z` (requires admin or project owner rights) |
 | `due_date`                                | string  | no       | Date time string in the format YEAR-MONTH-DAY, e.g. `2016-03-11` |
@@ -548,7 +548,7 @@ PUT /projects/:id/issues/:issue_iid
 | `description`  | string  | no       | The description of an issue                                                                                |
 | `confidential` | boolean | no       | Updates an issue to be confidential                                                                        |
 | `assignee_ids`  | Array[integer] | no  | The ID of the user(s) to assign the issue to. Set to `0` or provide an empty value to unassign all assignees.  |
-| `milestone_id` | integer | no       | The ID of a milestone to assign the issue to. Set to `0` or provide an empty value to unassign a milestone.|
+| `milestone_id` | integer | no       | The global ID of a milestone to assign the issue to. Set to `0` or provide an empty value to unassign a milestone.|
 | `labels`       | string  | no       | Comma-separated label names for an issue. Set to an empty string to unassign all labels.                   |
 | `state_event`  | string  | no       | The state event of an issue. Set `close` to close the issue and `reopen` to reopen it                      |
 | `updated_at`   | string  | no       | Date time string, ISO 8601 formatted, e.g. `2016-03-11T03:45:40Z` (requires admin or project owner rights) |

doc/api/merge_requests.md

@@ -539,7 +539,7 @@ POST /projects/:id/merge_requests
 | `description`              | string  | no       | Description of MR                                                               |
 | `target_project_id`        | integer | no       | The target project (numeric id)                                                 |
 | `labels`                   | string  | no       | Labels for MR as a comma-separated list                                         |
-| `milestone_id`             | integer | no       | The ID of a milestone                                                           |
+| `milestone_id`             | integer | no       | The global ID of a milestone                                                           |
 | `remove_source_branch`     | boolean | no       | Flag indicating if a merge request should remove the source branch when merging |
 | `allow_maintainer_to_push` | boolean | no       | Whether or not a maintainer of the target project can push to the source branch  |
 
@@ -622,7 +622,7 @@ PUT /projects/:id/merge_requests/:merge_request_iid
 | `target_branch`            | string  | no       | The target branch                                                               |
 | `title`                    | string  | no       | Title of MR                                                                     |
 | `assignee_id`              | integer | no       | The ID of the user to assign the merge request to. Set to `0` or provide an empty value to unassign all assignees.  |
-| `milestone_id`             | integer | no       | The ID of a milestone to assign the merge request to. Set to `0` or provide an empty value to unassign a milestone.|
+| `milestone_id`             | integer | no       | The global ID of a milestone to assign the merge request to. Set to `0` or provide an empty value to unassign a milestone.|
 | `labels`                   | string  | no       | Comma-separated label names for a merge request. Set to an empty string to unassign all labels.                    |
 | `description`              | string  | no       | Description of MR                                                               |
 | `state_event`              | string  | no       | New state (close/reopen)                                                        |