[Schema Inaccuracy] `issue.state_reason` missing enum variant: `duplicate`

Start by locating the OpenAPI schema definition for issue.state_reason shown in the issue, then use the provided curl command to confirm the API currently returns duplicate. Done means the enum lists duplicate alongside the existing variants and the schema accurately describes that response.

Schema Inaccuracy

(this issue was reposted from https://github.com/orgs/community/discussions/150535, cc https://github.com/yanyongyu/githubkit/issues/188)

Current definition:

      "state_reason": {
        "description": "The reason for the current state",
        "type": [
          "string",
          "null"
        ],
        "enum": [
          "completed",
          "reopened",
          "not_planned",
          null
        ],
        "examples": [
          "not_planned"
        ]
      },

Expected

duplicate listed among variants. Here's an issue with that state_reason (https://api.github.com/repos/python/mypy/issues/18584):

    {
        "active_lock_reason": null,
        "assignee": null,
        "assignees": [],
        "author_association": "CONTRIBUTOR",
        "body": "...",                                                                                                     
        "closed_at": "2025-02-02T16:24:49Z",
        "closed_by": {...},
        "comments": 1,
        "comments_url": "https://api.github.com/repos/python/mypy/issues/18584/comments",
        "created_at": "2025-02-01T23:28:55Z",
        "events_url": "https://api.github.com/repos/python/mypy/issues/18584/events",
        "html_url": "https://github.com/python/mypy/issues/18584",
        "id": 2825499430,
        "labels": [...],
        "labels_url": "https://api.github.com/repos/python/mypy/issues/18584/labels{/name}",
        "locked": false,
        "milestone": null,
        "node_id": "I_kwDOAGuhRc6oabMm",
        "number": 18584,
        "performed_via_github_app": null,
        "reactions": {...},
        "repository_url": "https://api.github.com/repos/python/mypy",
        "state": "closed",
        "state_reason": "duplicate",
        "sub_issues_summary": {
            "completed": 0,
            "percent_completed": 0,
            "total": 0
        },
        "timeline_url": "https://api.github.com/repos/python/mypy/issues/18584/timeline",
        "title": "Overloaded signature with `LiteralString` is seen as \"broader or same\" as `str`",
        "updated_at": "2025-02-02T16:24:50Z",
        "url": "https://api.github.com/repos/python/mypy/issues/18584",
        "user": {...}
    }

Reproduction Steps

$ curl -fs https://api.github.com/repos/python/mypy/issues/18584 | jq -r '.state_reason'
duplicate