Continue line comments

[TornaxO7]

Closes #1730

Continues #8664

This is my attempt to apply the changes of #4718 to the PR.

[TornaxO7]

One thing which bothers me is how we want to "continue" the comment from block comments like for C of this style:

/*
 * | <-- let's say here's the cursor, how should we "recognize" this `*`? Adding another entry in `language.toml` per language which should indicate which "multiblock-continuity" there are?
 */

Should this be tackled in this PR or in another PR? Should this be tackled at all?

[the-mikedavis]

Yeah good point, I hadn't thought to use C-w to remove the comment token. Kakoune's behavior for this is confusing and maybe buggy - enter sometimes strips the comment token but it depends on the language and context. Using C-w is more explicit and predictable and we should avoid ruining the experience of continuing a comment over multiple lines, for example adding an extra line to break up paragraphs in markdown in a Rust doc comment.

For that use-case specifically I believe we also want to be trimming whitespace under certain conditions in insert_newline, similar to #4854 but not just when the line is all whitespace. That way you can hit Enter Enter to continue a line comment twice and trim the trailing whitespace after the first continuation. I have a change locally to do this but I'll submit it after this is merged since it will conflict (only because of formatting changes)

[pascalkuthe]

I don't think this is a limitation we want to have in thr lognterm but usually autopairs within comments are a bit niche and likely hard to fix until some other changss land so this is probably fine for now.

[TornaxO7]

[eanyanwu]

This just made my night. Thank you @TornaxO7 & rest of the maintainers 🙌🏾 🙌🏾 for the steady progress.
It sure pays off to read through the latest commits every few days 😆

[TornaxO7]

You're welcome