Adding codetabs in _docs/request-matching page

[wernerblanck]

This PR adds codetabs in the docs/request-matching page, similar to the work done on the stubbing page.

References

• Add support for rendering code tabs #165

Submitter checklist

• The PR request is well described and justified, including the body and the references
• The PR title represents the desired changelog entry
• If the change against WireMock 2 functionality (incompatible with WireMock 3),
  it is submitted against the 2.x branch
• The repository's code style is followed (see the contributing guide)

Details: Contributor Guide

[tomakehurst]

Thanks!