text: Title: Check all links in docs and make them more accessible
  Body: Guidelines for links are as follows:
  
  * We should comply with https://vizro.readthedocs.io/en/stable/pages/development/documentation-style-guide/#language
  * Links should always work.
  
  ### Task (1) Fix all links
  Before we have perfection, we need to run through all the docs pages and fix issues like this one https://github.com/mckinsey/vizro/pull/422#discussion_r1566440210 where they arise.
  
  ### Task (2) Set up style checking for future content
  One way to enforce this ongoing would be to use Vale. I've asked how to do this:
  https://github.com/errata-ai/vale/discussions/807
  
  ### Task (3) Add external link checking (if not already running) to CI.
  We already have this for internal links in that we build with `--strict` but need to have something check links to Dash etc as Kedro does.
  
  
  This ticket doesn't need technical writing skills nor does it need Vale knowledge. Good first issue for a new contributor!