Update README.md

[chris-park]

Add instructions for getting around the dreaded error: Microsoft Visual C++ 14.0 or greater is required. Get it with "Microsoft C++ Build Tools" if you already have an existing MinGW C++ compiler.

[mathematicalmichael]

hopefully this one won't be necessary once upgraded wheels are published for annoy, but it's helpful for a few edge-cases (python 3.6/3.7, 3.14)
see wip here:
spotify/annoy#680

[williamsyy]

@chris-park Thank you for your contribution to PaCMAP — the guidelines you've proposed look great.

To keep the README.md clean and focused, would you consider creating a separate TROUBLESHOOTING.md file for this content? This helps centralize installation or usage issues in a discoverable and version-controlled way, especially when the topic may apply to a subset of users.

You can then link to the new file from a short section in the README.md, such as:

## Installation Issues?
See [TROUBLESHOOTING.md](./TROUBLESHOOTING.md) for solutions to common installation and usage problems.

This approach ensures the repo remains organized while still being helpful to users encountering edge cases. Again, thanks for your interest and contribution to PaCMAP!