Replace Hard-coded HTTP Verbs with Constants (#27219)

* Replace hard-coded HTTP verbs with constants in `net/http`

server/channels/web/static.go

@@ -47,7 +47,7 @@ func (w *Web) InitStatic() {
 		w.MainRouter.PathPrefix("/static/").Handler(staticHandler)
 		w.MainRouter.Handle("/robots.txt", http.HandlerFunc(robotsHandler))
 		w.MainRouter.Handle("/unsupported_browser.js", http.HandlerFunc(unsupportedBrowserScriptHandler))
-		w.MainRouter.Handle("/{anything:.*}", w.NewStaticHandler(root)).Methods("GET")
+		w.MainRouter.Handle("/{anything:.*}", w.NewStaticHandler(root)).Methods(http.MethodGet)
 
 		// When a subpath is defined, it's necessary to handle redirects without a
 		// trailing slash. We don't want to use StrictSlash on the w.MainRouter and affect