Fix broken links following change in trailingSlash

The previous commit changing trailingSlash handling to true introduced some broken links:

```
 Exhaustive list of all broken links found:
  - Broken link on source page path = /api-playbook/Governance/api_compliance/:
     -> linking to ../../api-playbook/ (resolved as: /api-playbook/api-playbook/)
  - Broken link on source page path = /api-playbook/Governance/developer_onboarding/:
     -> linking to ../../api-specifications/ (resolved as: /api-playbook/api-specifications/)
  - Broken link on source page path = /api-playbook/Support/creating_support_doc/:
     -> linking to ../../api-playbook/ (resolved as: /api-playbook/api-playbook/)
  - Broken link on source page path = /architecture-pillars/Development practices/api_compliance/:
     -> linking to ../../api-playbook/ (resolved as: /architecture-pillars/api-playbook/)
  - Broken link on source page path = /architecture-pillars/Development practices/developer_onboarding/:
     -> linking to ../../ways-of-working/ (resolved as: /architecture-pillars/ways-of-working/)
  - Broken link on source page path = /architecture-pillars/Reliability/core_resource_compliance/:
     -> linking to ../../api-playbook/ (resolved as: /architecture-pillars/api-playbook/)
```

Fixing these links to point directly to the source markdown file resolves the build failure and lets Docusaurus generate the correct final link (whether it has as trailing slash or not), so this approach is more robust.

Author: spikeheap

docs/api-playbook/Governance/api_compliance.md

@@ -10,7 +10,7 @@ The APIs compliance checklist will be used as part of future Service Standard As
 ### Checklist
 1. The API has corresponding SwaggerHub documentation for all of the API endpoints it exposes.
 2. The API has completed the [API specification assessment process](../../api-specifications/assessment_process.md)
-3. The API has been developed in Hackney’s preferred tech tech stack, unless otherwise agreed and as per standards defined in our [API playbook](../../api-playbook/).
+3. The API has been developed in Hackney’s preferred tech tech stack, unless otherwise agreed and as per standards defined in our [API playbook](../README.md).
 4. The API has been developed following the TDD approach and has end-to-end tets in place
     - End-to-end tests guide for DynamoDB
     - End-to-end tests guide for PostgreSQL

docs/api-playbook/Governance/developer_onboarding.md

@@ -46,7 +46,7 @@ All APIs must be built in a reusable manner, unless they implement a very specif
 We use [SwaggerHub](https://app.swaggerhub.com/organizations/Hackney) to document our APIs and their respective data contracts. All new and existing APIs must have corresponding SwaggerHub documentation. It is the responsibility of the engineers who amend existing APIs to also update the documentation so it is kept up-to-date.
 - If you or your team is building new APIs or making changes to existing API endpoints, please request SwaggerHub access so you can amend the specifications documented to ensure they are always up-to-date.
 
-In addition, we also have [API specifications](../../api-specifications/), which capture a summary of the user needs and any other findings related to an API.
+In addition, we also have [API specifications](../../api-specifications/README.md), which capture a summary of the user needs and any other findings related to an API.
 - A new API specification must be produced for all new APIs.
 - The API specification document should link off to the SwaggerHub page that outlines the API contract.
 - The API specification should be updated when the API introduces new endpoints or changes to existing functionality.

docs/api-playbook/Support/creating_support_doc.md

@@ -25,4 +25,4 @@ To create support documentation that is easy to find and becomes quickly availab
     - The item to be included should match the id you have given to the support document created.
 - Create a pull request with your changes.
 
-Once the changes are approved and merged, the support documentation will be available in the [API playbook](../../api-playbook/).
+Once the changes are approved and merged, the support documentation will be available in the [API playbook](../README.md).

docs/architecture-pillars/Development practices/api_compliance.md

@@ -10,7 +10,7 @@ The APIs compliance checklist will be used as part of future Service Standard As
 ### Checklist
 1. The API has corresponding SwaggerHub documentation for all of the API endpoints it exposes.
 2. The API has completed the [API specification assessment process](../../api-specifications/assessment_process.md)
-3. The API has been developed in Hackney’s preferred tech tech stack, unless otherwise agreed and as per standards defined in our [API playbook](../../api-playbook/).
+3. The API has been developed in Hackney’s preferred tech tech stack, unless otherwise agreed and as per standards defined in our [API playbook](../../api-playbook/README.md).
 4. The API has been developed following the TDD approach and has end-to-end tets in place
     - End-to-end tests guide for DynamoDB
     - End-to-end tests guide for PostgreSQL

docs/architecture-pillars/Development practices/developer_onboarding.md

@@ -6,7 +6,7 @@ We love innovation and are always open to learning, iterating and improving. To
 Our preferred BE stack is documented [here](../../api-playbook/Development%20Lifecycle/How%20to%20build%20an%20API/Preferred%20tech%20stack/Readme.md).
 
 ### Development standards
-All technical members of a project team must familiarise themselves with [Hackney’s development standards](../../ways-of-working/), which follow the Twelve Factor Application methodology. Those define the high level principles to follow when developing a digital product.
+All technical members of a project team must familiarise themselves with [Hackney’s development standards](../../ways-of-working/README.md), which follow the Twelve Factor Application methodology. Those define the high level principles to follow when developing a digital product.
 
 ### Playbooks
 
@@ -63,7 +63,7 @@ To set up your developer workstation, please refer to the Workstation Setup Guid
 ### Technical ways of working
 
 #### Pull Request process
-Hackney’s official pull request process to follow as part of the Software Development Lifecycle can be found [here](../../ways-of-working/).
+Hackney’s official pull request process to follow as part of the Software Development Lifecycle can be found [here](../../ways-of-working/README.md).
 
 ### API specifications
 All APIs must be built in a reusable manner, unless they implement a very specific use case. Any new proposed reusable APIs or changes to the data models of existing ones should follow the [API specification assessment process](../../api-specifications/assessment_process.md).

docs/architecture-pillars/Reliability/core_resource_compliance.md

@@ -1,7 +1,7 @@
 # Core AWS resources compliance checks
 
 ### Context
-At Hackney, we follow an infrastructure-as-code (IaC) approach and use Terraform to provision most of our AWS cloud resources. For our APIs, which are Lambda functions exposed via AWS API Gateway, we use the Serverless framework as it significantly speeds up the delivery and resource creation.  For more information please refer to [our playbook](../../api-playbook/).
+At Hackney, we follow an infrastructure-as-code (IaC) approach and use Terraform to provision most of our AWS cloud resources. For our APIs, which are Lambda functions exposed via AWS API Gateway, we use the Serverless framework as it significantly speeds up the delivery and resource creation.  For more information please refer to [our playbook](../../api-playbook/README.md).
 
 From a Development perspective, each project manages its own Terraform files(or Serverless configuration) to provision resources for our microservices and frontend applications. Terraform is then applied automatically as part of the CI/CD pipeline workflow during deployment.