feat: add hanging indent support for wrapped list items

[jy-tan]

Fixes issue #56 where list items that wrap to multiple lines did not have proper hanging indentation, causing continuation lines to align with the bullet/number instead of the text content.

Just taking a stab at this since I'd like to see this fixed, let me know if there's a better approach.

Before:

• Long item text that wraps across
multiple lines with no indent

After:

• Long item text that wraps across
  multiple lines with no indent

The fix works by:

1. Detecting list item prefixes in the plain text representation
2. Calculating reduced wrap width accounting for hanging indent space
3. Splitting prefix from content using ANSI-aware parsing
4. Wrapping content at the reduced width and prepending hanging indent to continuation lines
5. Passing pre-formatted text to MarginWriter, which preserves the spacing

[meowgorithm]

This is really nice; thanks for the contribution. I haven't personally reviewed this one yet but it's something I'd very much like to see merged; noting down internally.

[aymanbagabas]

@jy-tan Could you please change the base to make it against v2-exp? We're finalizing our v2 releases and this would be a great feature to have

[aymanbagabas]

We already provide ANSI aware wrapping logic for 7-bit and 8-bit sequences and UTF-8. We should probably use them instead of implementing a separate wrapping and parsing logic. Could you please explain the use case in details for consumeEscapeSequence and other wrapping functions?

https://github.com/charmbracelet/x/blob/main/ansi/wrap.go
https://github.com/charmbracelet/lipgloss/blob/v2-exp/wrap.go#L12

[aymanbagabas]

Why don't you use ANSI aware wrapping logic from charmbracelet/x/ansi and charmbracelet/lipgloss/v2?

[aymanbagabas]

Why do we need this?

[jy-tan]

Ah wasn't aware of those existing utils. Modified to use them now, let me know if this works.

[aymanbagabas]

Hey @jy-tan, thank you again for taking the time to work on this. You still haven't answered my questions above 🙂

Honestly, I don't understand why we need to do multiple ansi.Strip and split logic around the list items. I believe you can achieve that easily without the complicated logic via lipgloss.Wrap(...) and ansi.StringWidth(...). Check out this example to do hanging indent via Lip Gloss main.go