cmd: typo fixed, isntance -> instance (#17149)

cmd/utils/flags.go

@@ -998,7 +998,7 @@ func setEthash(ctx *cli.Context, cfg *eth.Config) {
 	}
 }
 
-// checkExclusive verifies that only a single isntance of the provided flags was
+// checkExclusive verifies that only a single instance of the provided flags was
 // set by the user. Each flag might optionally be followed by a string type to
 // specialize it further.
 func checkExclusive(ctx *cli.Context, args ...interface{}) {