api: fix overly strict edit pr permissions (#15900)

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: zeripath <art27@cantab.net>

routers/api/v1/api.go

@@ -888,7 +888,7 @@ func Routes() *web.Route {
 						Post(reqToken(), mustNotBeArchived, bind(api.CreatePullRequestOption{}), repo.CreatePullRequest)
 					m.Group("/{index}", func() {
 						m.Combo("").Get(repo.GetPullRequest).
-							Patch(reqToken(), reqRepoWriter(models.UnitTypePullRequests), bind(api.EditPullRequestOption{}), repo.EditPullRequest)
+							Patch(reqToken(), bind(api.EditPullRequestOption{}), repo.EditPullRequest)
 						m.Get(".diff", repo.DownloadPullDiff)
 						m.Get(".patch", repo.DownloadPullPatch)
 						m.Post("/update", reqToken(), repo.UpdatePullRequest)