我正在运行一个命令flutter devices来检查连接的设备，但它给出了以下错误：
flutter: The term 'flutter' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of
the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ flutter devices
+ ~~~~~~~
+ CategoryInfo : ObjectNotFound: (flutter:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
flutter devices