Fix formatting issues on label-management & branch-management pages

[cghyzel]

• Fixes #463
• Fixes formatting so that there is now a single header per example for:
  • https://docs.gitstream.cm/automations/standard/branch-management/
  • https://docs.gitstream.cm/automations/standard/label-management/
• Adds footers that are consistent with the parent page to:
  • https://docs.gitstream.cm/automations/standard/branch-management/enforce-branch-name
  • https://docs.gitstream.cm/automations/standard/label-management/enforce-labels
  • https://docs.gitstream.cm/automations/standard/label-management/label-approvals
  • https://docs.gitstream.cm/automations/standard/label-management/label-modified-resources
  • https://docs.gitstream.cm/automations/standard/label-management/label-prs-by-language
  • https://docs.gitstream.cm/automations/standard/label-management/label-resources-percent
  • https://docs.gitstream.cm/automations/standard/label-management/label-unresolved-threads
  • https://docs.gitstream.cm/automations/standard/label-management/suggest-labels

[gitstream-cm[bot]]

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