color.channel can not auto convert between spaces and wrong docs about it

[Mister-Hope]

Reproduction: https://sass-lang.com/playground/#eJwzNHAoLU5VUCpOLC62Ss7PyS9SsubiUgGzrBSU00zTzNPSgCIOKalJpekKYHG95IzEvLzUHA2IMh0F9fKMzJLUvNTiYnVNawAzfhqY

@use "sass:color";

$color: #f5f7ff;

@debug color.channel($color, 'whiteness');

$channel: Color #f5f7ff has no channel named whiteness.
  ╷
5 │ @debug color.channel($color, 'whiteness');
  │        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ╵
  - 5:8  root stylesheet

I don't think this is the expected behavior.

The docs says:

⚠️ Heads up!

Because color.whiteness() is redundant with color.channel(), it’s no longer recommended. Instead of color.whiteness($color), you can write color.channel($color, "whiteness").

However, the correct name should be lightness or blackness on the color space docs. Something worth noting is that the deprecation also requires users to convert color space manually, as color.channel won't do that. An exmaple here:

@use "sass:color";

$color: #f5f7ff;

// $channel: Color #f5f7ff has no channel named lightness.
@debug color.channel($color, 'lightness');
// works and return 98.0392156863%
@debug color.channel(color.to-space($color, hsl), 'lightness');

So I believe at least the docs needs an update.

If the current behavior of color.channel is a bug, and sass team believes a channel name could be returned with any legacy color space by automatically converted to a correct space behind the sence, then only whiteness and blackness should be corrected in docs.

Otherwise, every deprecation about color.channel should be corrected, like color.red($color) must be replaced by color.channel(color.to-space($color, rgb), 'red'), unless the developer is sure that $color MUST be in rgb space

[nex3]

color.channel($color, "whiteness") is valid, but only if the color is in the HWB color space (example). From the color.channel() documentation:

Returns the value of $channel in $space, which defaults to $color’s space.

When you call color.channel(#f5f7ff, "whiteness"), the $space argument defaults to rgb because that's the color space of hex colors. If you explicitly pass $space: hwb, it will work regardless of the space of the input color (example).

It is probably worth adding the explicit $space parameter to the deprecation.