Fix Terraform provider documentation examples and formatting

[LutaoX]

What does this PR do?

• Fixed the terraform examples (note that instead of yml, I used hcl)
• added link to terraform provider registry doc in the respective section: https://registry.terraform.io/providers/temporalio/temporalcloud/latest/docs/resources/namespace

Notes to reviewers

This is in response to this open issue: #4093

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Project	Deployment	Review	Updated (UTC)
temporal-documentation	Ready	Preview, Comment	Jan 15, 2026 6:53pm