chore(nat): unify aotumatically code style and fix some error in test cases

[deer-hang]

What this PR does / why we need it:

Unify aotumatically code style and fix some error in test cases.

Which issue this PR fixes:
(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)
fixes #xxx

Special notes for your reviewer:

Release note:

PR Checklist

• Tests added/passed.

make testacc TEST='./huaweicloud/services/acceptance/nat' TESTARGS='-run TestAccData'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./huaweicloud/services/acceptance/nat -v -run TestAccData -timeout 360m -parallel 4
=== RUN   TestAccDatasourceDnatRules_basic
=== PAUSE TestAccDatasourceDnatRules_basic
=== RUN   TestAccDataPublicGateway_basic
=== PAUSE TestAccDataPublicGateway_basic
=== RUN   TestAccDatasourcePublicGateways_basic
=== PAUSE TestAccDatasourcePublicGateways_basic
=== RUN   TestAccDatasourcePrivateDnatRules_basic
=== PAUSE TestAccDatasourcePrivateDnatRules_basic
=== RUN   TestAccDatasourcePrivateGateways_basic
=== PAUSE TestAccDatasourcePrivateGateways_basic
=== RUN   TestAccDatasourcePrivateSnatRules_basic
=== PAUSE TestAccDatasourcePrivateSnatRules_basic
=== RUN   TestAccDatasourcePrivateTransitIps_basic
=== PAUSE TestAccDatasourcePrivateTransitIps_basic
=== RUN   TestAccDatasourceSnatRules_basic
=== PAUSE TestAccDatasourceSnatRules_basic
=== RUN   TestAccDatasourceSnatRules_direct
=== PAUSE TestAccDatasourceSnatRules_direct
=== CONT  TestAccDatasourceDnatRules_basic
=== CONT  TestAccDatasourcePrivateSnatRules_basic
=== CONT  TestAccDatasourcePrivateDnatRules_basic
=== CONT  TestAccDatasourcePrivateGateways_basic
--- PASS: TestAccDatasourcePrivateSnatRules_basic (73.97s)
=== CONT  TestAccDatasourcePublicGateways_basic
--- PASS: TestAccDatasourcePrivateGateways_basic (74.47s)
=== CONT  TestAccDatasourcePrivateTransitIps_basic
--- PASS: TestAccDatasourcePrivateTransitIps_basic (93.52s)
=== CONT  TestAccDatasourceSnatRules_direct
--- PASS: TestAccDatasourcePublicGateways_basic (101.25s)
=== CONT  TestAccDataPublicGateway_basic
--- PASS: TestAccDatasourcePrivateDnatRules_basic (209.62s)
=== CONT  TestAccDatasourceSnatRules_basic
--- PASS: TestAccDatasourceDnatRules_basic (215.55s)
--- PASS: TestAccDataPublicGateway_basic (77.17s)
--- PASS: TestAccDatasourceSnatRules_direct (86.45s)
--- PASS: TestAccDatasourceSnatRules_basic (84.17s)
PASS
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/nat       293.833s

• Documentation updated.

• Schema updated.

• CheckDeleted.

  • a. During query operation (Read Context)
    aa. Resource not found
    >>>>>> Paste the screenshot here <<<<<<

  • b. During delete/disassociate/unbind operation (Delete Context)
    ba. Resource not found
    >>>>>> Paste the screenshot here <<<<<<

[github-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This PR has been approved by: @deer-hang

[jinyangyang222]

/lgtm