Set font for dim characters

[valpackett]

WezTerm supports targeting dim (half intensity) characters for setting fonts like so:

	font_rules = {
		{ intensity = 'Half', italic = true, font = wezterm.font("Monaspace Radon Light") },
		{ intensity = 'Half', font = wezterm.font("Monaspace Krypton ExtraLight") },
		{ italic = true, font = wezterm.font("Monaspace Radon") },
	},

would be nice to be able to set fonts.dim, fonts.dim-italic etc.