[feature request] Add "unit test" modifier to the removeDuplicatedValues option

[Bub-la-bub]

This plugin works very well and the 'removeDuplicatedValues' feature is very useful for allowing "conscious duplicates" as you mention in the documentation and I think it could also be useful to add a modifier to the removeDuplicatedValues option which modifies the current behavior so that it tests the units of the value when deciding if the "duplicate" value should be removed. It could also be useful to allow "0" to be considered to have the same unit.

Examples:

// these have the same 'px' unit, so the last one would be kept:
margin-right: 10px;
margin-right: 5px;

// these have different units, so they both would be kept (same as current behavior):
margin-right: 1rem;
margin-right: 5px;

// these have no units, so they both would be kept (same as current behavior):
display: inline;
display: initial;

With the "0" rule mentioned above:

// the last one would be kept:
margin-right: 10px;
margin-right: 0;

// the last one would be kept:
margin-right: 0;
margin-right: 10px;

Anyway, thank you for making such a useful plugin.

[ChristianMurphy]

Also would you be interested in opening a pull request?