[xi-core-lib] Missing panic conditon on docs

[HeeillWang]

Style::new() has assert statement, but panic condition is missing on rust docs. Better to add panic condition like other crates' api

xi-editor/rust/core-lib/src/styles.rs

Lines 80 to 102 in a2dea30

	pub fn new<O32, O16, OB>(
	priority: u16,
	fg_color: O32,
	bg_color: O32,
	weight: O16,
	underline: OB,
	italic: OB,
	) -> Self
	where
	O32: Into<Option<u32>>,
	O16: Into<Option<u16>>,
	OB: Into<Option<bool>>,
	{
	assert!(priority <= 1000);
	Style {
	priority,
	fg_color: fg_color.into(),
	bg_color: bg_color.into(),
	weight: weight.into(),
	underline: underline.into(),
	italic: italic.into(),
	}
	}