feat(terraform_fmt): Add support for .tftest.hcl and .tfmock.hcl formatting (#911)

Both supported in https://github.com/hashicorp/terraform/blob/0c63fb2b097edcd5cb1a91322765a414206fbea2/internal/command/fmt.go#L30-L35

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Co-authored-by: Maksym Vlasov <[email protected]>

Author: nikolaik

.pre-commit-hooks.yaml

@@ -13,7 +13,9 @@
     Rewrites all Terraform configuration files to a canonical format.
   entry: hooks/terraform_fmt.sh
   language: script
-  files: \.(tf|tofu|tfvars)$
+  # Supported extensions by Terraform specified in
+  # https://github.com/hashicorp/terraform/blob/0c63fb2b097edcd5cb1a91322765a414206fbea2/internal/command/fmt.go#L30-L35
+  files: \.(tf|tofu|tfvars|tftest\.hcl|tfmock\.hcl)$
   exclude: \.terraform/.*$
 
 - id: terraform_docs