Proposal: update stylenames for SOFT axis to sort alphabetically

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Request: approval from Dave. I can make a PR if that is better.

Current problem

With the SOFT axis style names of Sharp, Soft, and ExtraSoft, many apps will list the resulting static fonts in a non-intuitive order, going from Sharp to ExtraSoft to Soft:

It seems unclear in the axis definitions whether certain style names should be elided (default names excluded from font/style names, like "Regular" or "Roman"), but if we didn’t elide Sharp, the ordering would be even worse, as ExtraSoft, Sharp, Soft.

Proposed solution

Instead, we should change the SOFT axis definition in two ways:

1. Make “Sharp” an elided name (it’s just the default, and @sponcey specifically wishes to avoid the name “Sharp” displaying in the Fraunces font naming because the concept of Fraunces is softness.
2. Make the SOFT=100 stylename SuperSoft, rather than Extra Soft, for better sorting of font names. (See the discussion at Make full release (variable + static) for GitHub, then link to it from Fraunces site undercasetype/Fraunces#186 (comment) where we come to this conclusion)