- use latest [5.11.0](https://github.com/swagger-api/swagger-ui/releases/tag/v5.11.0) instead of the 2 years outdated [4.5.0](https://github.com/swagger-api/swagger-ui/releases/tag/v4.5.0)
  - it seems like the version was taken directly from [the SwaggerUI installation docs](https://github.com/swagger-api/swagger-ui/blob/v5.11.0/docs/usage/installation.md#unpkg), which still has an old version listed
    - in fact, the entire code block was taken from the doc
      - significantly simplify the code block as it renders inside of existing MD/HTML
        - a second `DOCTYPE`, `html`, `head`, `body`, etc tags are actually invalid HTML, but either `mkdocs` ignored some of those or browsers just ignore some of those
          - fixing invalid HTML makes this doc page more robust
      - also fix the indentation in the code block too, which also did not meet style guidelines

- this seems to make it slightly more performant, which is our main issue, but also has other benefits of using a current version of a dep

- add a `markdownlint-disable` comment to allow the inline HTML
  - add a comment describing why it's necessary
    - similarly add a comment to the PR template explaining why that one is necessary too
  - remove the `Makefile`'s ignore on `swagger.md` for docs linting et al

Signed-off-by: Anton Gilgur <agilgur5@gmail.com>

Signed-off-by: Anton Gilgur <4970083+agilgur5@users.noreply.github.com>