chore: verify plopfile.ts autodetect

[benallfree]

I verified that --plopfile is not necessary and that plopfile.ts is auto-detected.

[awhitford]

It is autodetected. However, if there is a plopfile.js and a plopfile.ts, then I've observed that it loads the plopfile.js instead of the plopfile.ts even when using tsx. I suggest clearly documenting this behavior.