docs: correct wait_for_pool_ready default value in documentation

[juchom]

Adjust documentation to match code

terraform-provider-scaleway/internal/services/k8s/pool.go

Lines 101 to 106 in f5d4aa6

	"wait_for_pool_ready": {
	Type: schema.TypeBool,
	Optional: true,
	Default: true,
	Description: "Whether to wait for the pool to be ready",
	},

[remyleone]

Thanks a lot for your contribution @juchom :)