docs: Update broken Terraform documentation links

docs/decisions/infra/0004-separate-terraform-backend-configs-into-separate-config-files.md

@@ -8,7 +8,7 @@
 
 Up until now, most projects adopted an infrastructure module architecture that is structured as follows: Each application environment (prod, staging, etc) is a separate root module that calls a template module. The template module defines all the application infra resources needed for an environment. Things that could be different per environment (e.g. desired ECS task count) are template variables, and each environment can have local vars (or somewhat equivalently, a tfvars file) that customizes those variables. Importantly, each environment has its own backend tfstate file, and the backend config is stored in the environment module’s `main.tf`.
 
-An alternative approach exists to managing the backend configs. Rather than saving the backend config directly in `main.tf`, `main.tf` could contain a [partial configuration](https://developer.hashicorp.com/terraform/language/settings/backends/configuration#partial-configuration), and the rest of the backend config would be passed in during terraform init with a command like `terraform init --backend-config=prod.s3.tfbackend`. There would no longer be a need for separate root modules for each environment. What was previously the template module would instead act as the root module, and engineers would work with different environments solely through separate tfbackend files and tfvar files. Doing this would greatly simplify the module architecture at the cost of some complexity when executing terraform commands due to the extra command line parameters. To manage the extra complexity of running terraform commands, a wrapper script (such as with Makefile commands) can be introduced.
+An alternative approach exists to managing the backend configs. Rather than saving the backend config directly in `main.tf`, `main.tf` could contain a [partial configuration](https://developer.hashicorp.com/terraform/language/backend#partial-configuration), and the rest of the backend config would be passed in during terraform init with a command like `terraform init --backend-config=prod.s3.tfbackend`. There would no longer be a need for separate root modules for each environment. What was previously the template module would instead act as the root module, and engineers would work with different environments solely through separate tfbackend files and tfvar files. Doing this would greatly simplify the module architecture at the cost of some complexity when executing terraform commands due to the extra command line parameters. To manage the extra complexity of running terraform commands, a wrapper script (such as with Makefile commands) can be introduced.
 
 The approach can be further extended to per-environment variable configurations via an analogous approach with [variable definitions files](https://developer.hashicorp.com/terraform/language/values/variables#variable-definitions-tfvars-files) which can be passed in with the `-var-file` command line option to terraform commands.
 

docs/infra/set-up-aws-account.md

@@ -2,7 +2,7 @@
 
 The AWS account setup process will:
 
-1. Create the [Terraform backend](https://www.terraform.io/language/settings/backends/configuration) resources needed to store Terraform's infrastructure state files. The project uses an [S3 backend](https://www.terraform.io/language/settings/backends/s3).
+1. Create the [Terraform backend](https://developer.hashicorp.com/terraform/language/backend) resources needed to store Terraform's infrastructure state files. The project uses an [S3 backend](https://www.terraform.io/language/settings/backends/s3).
 2. Create the [OpenID connect provider in AWS](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html) to allow GitHub Actions to access AWS account resources.
 3. Create the IAM role and policy that GitHub Actions will use to manage infrastructure resources.
 

infra/README.md

@@ -55,7 +55,7 @@ This project has the following AWS environments:
 - `staging`
 - `prod`
 
-The environments share the same root modules but will have different configurations. Backend configuration is saved as [`.tfbackend`](https://developer.hashicorp.com/terraform/language/settings/backends/configuration#file) files. Most `.tfbackend` files are named after the environment. For example, the `[app_name]/service` infrastructure resources for the `dev` environment are configured via `dev.s3.tfbackend`. Resources for a module that are shared across environments, such as the build-repository, use `shared.s3.tfbackend`. Resources that are shared across the entire account (e.g. /infra/accounts) use `<account name>.<account id>.s3.tfbackend`.
+The environments share the same root modules but will have different configurations. Backend configuration is saved as [`.tfbackend`](https://developer.hashicorp.com/terraform/language/backend#file) files. Most `.tfbackend` files are named after the environment. For example, the `[app_name]/service` infrastructure resources for the `dev` environment are configured via `dev.s3.tfbackend`. Resources for a module that are shared across environments, such as the build-repository, use `shared.s3.tfbackend`. Resources that are shared across the entire account (e.g. /infra/accounts) use `<account name>.<account id>.s3.tfbackend`.
 
 ### 🔀 Project workflow