Tweaks to docs for fields that can be empty

Follow up to #2662

docs/cluster_spec.md

@@ -135,7 +135,7 @@ Will result in the flag `--runtime-config=batch/v2alpha1=true,apps/v1alpha1=true
 
 This block contains configurations for `kubelet`.  See https://kubernetes.io/docs/admin/kubelet/
 
-NOTE: Arguments can be set to empty if the field is included in the spec, and an empty string is passed to it.
+NOTE: Where the corresponding configuration value can be empty, fields can be set to empty in the spec, and an empty string will be passed as the configuration value.
  ```yaml
  spec:
    kubelet:

pkg/flagbuilder/buildflags_test.go

@@ -28,7 +28,7 @@ func stringPointer(s string) *string {
 	return &s
 }
 
-func int34Pointer(i32 int32) *int32 {
+func int32Pointer(i32 int32) *int32 {
 	return &i32
 }
 
@@ -94,7 +94,7 @@ func TestKubeletConfigSpec(t *testing.T) {
 		},
 		{
 			Config: &kops.KubeletConfigSpec{
-				LogLevel: int34Pointer(2),
+				LogLevel: int32Pointer(2),
 			},
 			Expected: "--v=2",
 		},