Add graphics units to NumberFormat

[devongovett]

CLDR includes a category of units for graphics, such as pixels, dots per inch, ems, etc. These are useful in software such as design tools, photo editing tools, etc. to describe objects on screen. It would be useful for Intl.NumberFormat to support these units so applications can properly internationalize these types of values without embedding the translations themselves.

Here are the definitions for the units in CLDR: https://github.com/unicode-org/cldr/blob/5b309e1c53f443f333998cf49cb70614619bb677/common/main/en.xml#L6433-L6472

[longlho]

@sffc what's the process of proposing more units? We also got request from formatjs/formatjs#2398

[sffc]

If we have enough evidence that this feature request has broad appeal, and that these units are at least as useful as other units that are already in ECMA-402, then this feature request should pass the bar for new ECMA-402 proposals.

Create a proposal repo (might I suggest "proposal-intl-graphics-units") by using template-for-proposals, then add it to the agenda under the projects tab.

As long as all the delegates are onboard with the idea, this proposal will be fairly easy; we can probably get it to Stage 2 in one shot and then Stage 3 soon after.

[zbraniecki]

@sffc I think @longlho question is broader than "how to add a unit".

I'd like to understand also the reverse of that equation - what would make us reject such request?

Otherwise, I'm not sure what stops the kitchen sink approach of accruing units as people request them.

[sffc]

We should use the same standards for new units as for any other new proposal. We have spent a lot of time drafting #512. The proposal champion just needs to demonstrate that adding new units meets those criteria. If the committee cannot come to consensus that the proposal meets them, then we reject the proposal from Stage 2 advancement.

[zbraniecki]

I'm convinced.