[css-typed-om] definition of CSSMathValue.equals() should be a little clearer

[dbaron]

The definition of CSSMathValue.equals() seems to lack a bit of formality in the final step. In particular, the final step currently begins with:

If all items in thisAndValues are of type CSSMathValue:

and then has two options that require iterating over a bunch of values.

The text doesn't actually say how to take this iteration and produce a single result (true or false) from the equals function. It probably should.

It also feels like the wording could be clearer in other ways, e.g., in terms of describing what exactly is being iterated over and how many recursive calls to the algorithm are made.