Fix regex on route file (#3851)

cmd/web.go

@@ -586,12 +586,12 @@ func runWeb(ctx *cli.Context) error {
 			m.Get("/src/*", repo.Home)
 			m.Get("/raw/*", repo.SingleDownload)
 			m.Get("/commits/*", repo.RefCommits)
-			m.Get("/commit/:sha([a-z0-9]{7,40})$", repo.Diff)
+			m.Get("/commit/:sha([a-f0-9]{7,40})$", repo.Diff)
 			m.Get("/forks", repo.Forks)
 		}, context.RepoRef())
-		m.Get("/commit/:sha([a-z0-9]{7,40})\\.:ext(patch|diff)", repo.RawDiff)
+		m.Get("/commit/:sha([a-f0-9]{7,40})\\.:ext(patch|diff)", repo.RawDiff)
 
-		m.Get("/compare/:before([a-z0-9]{7,40})\\.\\.\\.:after([a-z0-9]{7,40})", repo.CompareDiff)
+		m.Get("/compare/:before([a-z0-9]{40})\\.\\.\\.:after([a-z0-9]{40})", repo.CompareDiff)
 	}, ignSignIn, context.RepoAssignment(), repo.MustBeNotBare)
 	m.Group("/:username/:reponame", func() {
 		m.Get("/stars", repo.Stars)