Optimize LineText::color

[zhiburt]

We could eliminate most of the ANSI here

tabled/tabled/src/settings/style/line_text.rs

Lines 115 to 125 in 706f30d

	/// let mut table = Table::new(["Hello World"]);
	/// table.with(LineText::new("TABLE", Rows::first()).color(Color::FG_BLUE));
	///
	/// assert_eq!(
	/// table.to_string(),
	/// "\u{1b}[34mT\u{1b}[39m\u{1b}[34mA\u{1b}[39m\u{1b}[34mB\u{1b}[39m\u{1b}[34mL\u{1b}[39m\u{1b}[34mE\u{1b}[39m---------+\n\
	/// | &str |\n\
	/// +-------------+\n\
	/// | Hello World |\n\
	/// +-------------+"
	/// );

[zhiburt]

Maybe we must optimize the underlying structures to handle Spans rather then chars.
So we could save memory and eliminate number of lookups?
Though the insert be harder I guess