Add ratio-simplified rule

[FloEdelmann]

What is the problem you're trying to solve?

aspect-ratio: 3 / 4 is the same as aspect-ratio: 6 / 8, but if they are inconsistent in the codebase, it's difficult to find them both with a single search.

Note that 0.75 is also equivalent, but there is already another rule suggestion for choosing between integers and decimal style:

• Add ratio-notation #6575

What solution would you like to see?

A new rule ration-simplified that reports 6 / 8 because it can be simplified to 3 / 4 because both numerator and the denominator are divisible by 2 (i.e. greatest common divisor is not 1). See also https://stackoverflow.com/questions/7777142/how-to-simplify-a-fraction.

[ybiquitous]

@FloEdelmann Thanks for the proposal. I'm unsure how many use cases there are, but I can understand your argument.

Probably, I guess it matters whether this new rule is "generally useful; not tied to idiosyncratic patterns" as our document says.

I'd like to hear other members' thoughts.