Markdown marks serialization configuration override

[maayanalgresie]

Problem Statement
Currently, PlateJS doesn't provide a clean way to override the markdown serialization for built-in marks (bold, italic, etc.). While custom rules can be added for custom node types, built-in marks like bold have hardcoded serialization behavior that cannot be easily customized.

Use Case
Slack Markdown Format Support: Slack uses a different markdown format where:

Bold text uses single asterisks: *bold*
Italic text uses underscores: _italic_

But standard markdown uses:

Bold text uses double asterisks: **bold**
Italic text uses single asterisks: *italic*

[felixfeng33]

The platejs rules only provide control over the property level in terms of permissions. For the parsing layer, more knowledge of the "remark world" is generally required.

Not sure if it will works - create a new custom a new remark plugin called something like remarkSlackBold to parse *bold* as bold instead of italic.

[maayanalgresie]

@felixfeng33
I tried it, it didn't work for me,
I tried both create new remark plugin and trying to override the markdown rules.
Both didn't work for me.

I think we should have control on the input output markdown format wdyt?

[felixfeng33]

Not sure why custom remarkjs plugin not working in plate, but if it works without plate, it might require adjustments to plate's markdown package.