Inheriting trailingComma from Svelte

[ryanatkn]

The trailingComma setting (Prettier docs) is one that has changed in every major Prettier version from 1 to 3, and can't please everyone. I see reasonable arguments for all of these, and given tsv's policy to "just copy Svelte", I made 'none' the behavior in v0.2. I think this is probably the most off-beat choice in Svelte's .prettierrc hence this post about it. Discussion is welcome, but note the wontfix tag - tsv diverging from Svelte's explicit choices is unlikely to change. Your feedback here could be a signal to its maintainers but I'm intentionally tying my hands on choices like these.

'none' (Svelte & SvelteKit, Prettier v1, tsv's v0.2 behavior)

obj = {
	a,
	b
}

fn(
	a,
	b
)

'all' (Prettier's default v3+ and tsv's initial v0.1 behavior)

obj = {
	a,
	b,
}

fn(
	a,
	b,
)

'es5' (MDsveX, , Prettier v2)

obj = {
	a,
	b,
}

fn(
	a,
	b
)

Overall, tsv prioritizes readability over writability, and aims to fit smoothly into the official Svelte repos. I'm good with 'none' personally, and things have historically worked out well when I defer conflicting choices to the official Svelte patterns.