notifications write-APIs should return the modified notifications

[noerw]

• Gitea version (or commit ref): 1.16.0+dev-109-gd17f555fe

Description

The following endpoints return an empty response, whereas it would be useful to get the notifications back that were affected by the request:

• PUT /api/v1/notifications
• PUT /api/v1/repos/:owner/:repo/notifications
• PATCH /api/v1/notifications/threads/:id

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also, while we're at it:
The NotificationSubject struct contains URL and LatestCommentURL fields, but a fieldf WebURL and LatestCommentWebURL would be quite handy