Add links for platform-level docs

[freakboy3742]

• Add links to the platform docs matrix directly to the macOS/Windows page, rather than needing to go via the format pages.
• Clarified the Visual Studio components that are required (since it wasn't clear that there are 2 different v143 tool sets)
• Corrected the markup of Visual Studio install requirements.

PR Checklist:

• I will abide by the BeeWare Code of Conduct
• I have read and have followed the CONTRIBUTING.md file
• This PR was generated or assisted using an AI tool