[ygp] 16F5C, 16F60, 16F73, (16F74): 'C'-bowl inner arm needs to be shorter

[cheuk879]

Above are glyph shapes users have been using & prefer. In glyphs 1, 2, & 4, notice the internal side of the bowl that joins the vertical tail is shorter than the external side. For comparison, the default in build 194 has a symmetric bowl as shown below:

[cheuk879]

BTW, 16F74 is another in this series with the same base shape but different orientation. It's not in their alphabet, but a corresponding variant may be provided if it is desired to complete the series.

[jvgaultney]

This style was the default style in Shishan, however MiaoUnicode (which has informed most of the design decisions for Shimenkan) does not do this. We can add in a whole set of alternate glyphs and add yet another feature to substitute them, but it may affect more than just those four. Note the following shapes from Shishan:

Should this new feature affect the five other glyphs shown? And is this [ygp] only?

[cheuk879]

After a year of feedback collection only [ygp] came up with this, & that for only the captioned chars. The other chars are not used by them, & those groups who do use them have never remarked there's anything wrong with our Shimenkan glyph samples. So I guess we can just focus on the captioned chars.

[jvgaultney]

Great - thanks - that's helpful. I'll add only the three that are definitely needed, and add them to the [ygp] specific feature. Glyphs needed: u16F5C.ygp, u16F60.ygp, u16F73.ygp.

[jvgaultney]

Needed to add .mark.ygp versions too, for a total of 6 glyphs. Here are the designs in all weights:

[jvgaultney]

Please review these and let us know if they are OK.

[cheuk879]

Looks great :)