Colors in .item-color-visited() using deprecated variables

[swashbuck]

Subject of the issue

The .item-color-visited() mixin still references the deprecated variables @visited and @visited-inverted. All of the other styles here use the newer @item-foo variables.

adapt-contrib-vanilla/less/_defaults/_buttonMixins/_item.less

Lines 28 to 32 in 32e4fbe

	.item-color-visited() {
	background-color: @visited;
	color: @visited-inverted;
	}

@kirsty-hames Is there a reason why we've kept this one using the deprecated variables? If not, should they now use @item-color-visited and @item-color-inverted-visited? There is a note that @visited is only used by presentation components. However, as it's marked deprecated, is the assumption that it will eventually be removed?

Note that I was specifically looking at Accordion here.

adapt-contrib-vanilla/less/_defaults/_colors.less

Lines 46 to 54 in 32e4fbe

	// DEPRECATED
	// replaced by @item-color-visited and @item-color-inverted-visited
	// Note: @visited is only used by presentation components
	@visited: darken(@item-color, 15%);
	@visited-inverted: @item-color-inverted;
	//
	@item-color-visited: @visited;
	@item-color-inverted-visited: @visited-inverted;

[kirsty-hames]

Hey @swashbuck, yes @visited is deprecated. We left this in for legacy support but added the note to remove at a later date (next major release / breaking change etc). The note "@visited is only used by presentation components" is purely for context. from when we did a review of variable use.
Seeing as we only need @visited for legacy support, we can replace any styles referencing this with the new variable @item-color-visited.

Note, the theme.schema still uses visited. We kept this the same for backwards compatibility. When we remove the deprecated variable, we should update the schema at the same time. Should we just add a comment and keep as is or do you have any suggestions?