Clarify application of font variant (#1084).

[skynavga]

Closes #1084.

[palemieux]

Since it is now clear that tts:fontVariant does not apply to ruby containers, which cannot contain child glyph areas, these ruby containers should be removed from the list of elements to which this style property applies (see #1043 and #1071).

[skynavga]

Regarding #1085 (review), a ruby container is not an element, and, therefore, cannot be removed from the set { span }. You comment is non-actionable.

[css-meeting-bot]

The Timed Text Working Group just discussed font variant.

The full IRC log of that discussion

<cyril> Topic: font variant
<cyril> github: https://github.com//pull/1085
<cyril> pal: same for me
<cyril> nigel: I don't have an objection
<cyril> ... anyone has an objection>
<cyril> s/>/?/
<cyril> ... none
<cyril> ... we're happy to accept this

[palemieux]

This does not resolve #1043 but provides a valuable clarification.