Option to always output markdown BulletList as 'tight' (in GFM, etc)

[0xdevalias]

Describe your proposed improvement and the problem it solves.

I would like to be able to force GitHub Flavoured Markdown output's BulletList's to always use 'tight' output; and never loose.

I would imagine this would be configurable as an option, as not everyone would want it this way; and it would probably make the most sense if all markdown outputs supported it, not just GFM.

Describe alternatives you've considered.

Mostly custom filters and custom writers, though it's been quite a while since I was looking into those for this use case; and it feels like a lot of extra boilerplate work just to tweak one little part of how it outputs.

Some tangentially related issues:

• suggestions for tight/loose lists #671
• Config file for markdown output options? #5584
• Markdown writer: fully customizable list markers #10479
• Allow markdown Emph / BulletList characters to be customised (eg. * vs _, and - vs *) #10527
  • Allow markdown Emph / BulletList characters to be customised (eg. * vs _, and - vs *) #10527 (comment)
• Improve pandoc.scaffolding section in 'Pandoc Lua Filters' docs (RE: Custom Writers) #10531
• etc?