docs(routergroup.go): improve documentation

Signed-off-by: bestgopher <84328409@qq.com>

routergroup.go

@@ -94,15 +94,15 @@ func (group *RouterGroup) handle(httpMethod, relativePath string, handlers Handl
 // The last handler should be the real handler, the other ones should be middleware that can and should be shared among different routes.
 // See the example code in GitHub.
 //
-// For GET, POST, PUT, PATCH and DELETE requests the respective shortcut
+// For GET, POST, PUT, PATCH, DELETE, OPTIONS and HEAD requests the respective shortcut
 // functions can be used.
 //
 // This function is intended for bulk loading and to allow the usage of less
 // frequently used, non-standardized or custom methods (e.g. for internal
 // communication with a proxy).
 func (group *RouterGroup) Handle(httpMethod, relativePath string, handlers ...HandlerFunc) IRoutes {
 	if matched := regEnLetter.MatchString(httpMethod); !matched {
-		panic("http method " + httpMethod + " is not valid")
+		panic("http method " + httpMethod + " is invalid")
 	}
 	return group.handle(httpMethod, relativePath, handlers)
 }