Update HTTP status codes to modern codes (#18063)

* 2xx/3xx/4xx/5xx -> http.Status...
* http.StatusFound -> http.StatusTemporaryRedirect
* http.StatusMovedPermanently -> http.StatusPermanentRedirect

routers/web/goget.go

@@ -48,7 +48,7 @@ func goGet(ctx *context.Context) {
 	</body>
 </html>
 `))
-		ctx.Status(400)
+		ctx.Status(http.StatusBadRequest)
 		return
 	}
 	branchName := setting.Repository.DefaultBranch