Should fix-vf-meta set a flag value for the "regular" values to set ELIDABLE_AXIS_VALUE_NAME?

[thundernixon]

As I understand it, the Flags value of and entry in the AxisValue fields of the STAT table specify which instances have names that can be left out of composed font names.

I'm unclear on this, but based on what I can tell from the (MS OT STAT Flags spec](https://docs.microsoft.com/en-us/typography/opentype/spec/stat#flags), it seems that for an AxisValue like "Regular," the flags should be set to 2 rather than 0, as a current process of fontmake + fix-vf-meta will result in.

The spec says of the ELIDABLE_AXIS_VALUE_NAME value:

If set, it indicates that the axis value represents the “normal” value for the axis and may be omitted when composing name strings.

This is different from the elidedFallbackNameID, which I didn't initially realize. Whereas the 2 of the elidedFallbackNameID refers to nameID 2, the 2 in the Flags value would just state an axis value can be left out of composed names. I'm not sure how vital this is, however, as MS Word already does leave the "Regular" name off of composed font names.

Here's a current Regular entry:

<AxisValue index="1" Format="1">
    <AxisIndex value="0"/>
    <Flags value="0"/>
    <!-- Regular -->
    <ValueNameID value="259"/>
    <Value value="400.0"/>
</AxisValue>

Here's what I suspect it should be (line 3 changed):

<AxisValue index="1" Format="1">
    <AxisIndex value="0"/>
    <Flags value="2"/>
    <!-- Regular -->
    <ValueNameID value="259"/>
    <Value value="400.0"/>
</AxisValue>

I'm posting this because I've been looking into this value, and I think it could be a spot where we could slightly improve the meta fixer. However, I have uncertainty on whether I'm reading the spec in a completely correct way, so if I am misunderstanding the Flags entry, we shouldn't change this.

[thundernixon]

Here's a particular example that seems to indicate that Flags should be set as I suggested above:

example source

[m4rc1e]

Good find. I'll look into this on Monday.

[davelab6]

Great work Stephen!!

[m4rc1e]

This has been fixed in #237