[webvtt] Issue: incomplete ruby implementation [I18N-ISSUE-431] marked as i18n

r12a has just labeled an issue for https://github.com/w3c/webvtt as 
"i18n":

== incomplete ruby implementation [I18N-ISSUE-431] ==
[moving to github from 
https://www.w3.org/Bugs/Public/show_bug.cgi?id=28265]

i was just reviewing this with a mind to close our i18n tracker issue 
for now (and reopen as support for the other aspects of the html5 
markup model spreads), when it occurred to me that webvtt doesn't 
support the `rb` element.  

This is widely supported in browsers (see the test results at 
http://www.w3.org/International/tests/repo/results/ruby-html#position),
 and i think it should therefore be supported by webvtt.  Adding it 
allows for additional styling options, as well as reducing the 
potential for confusion in authors, who are used to using it in HTML.

Note that HTML5 supports all of the following:

```
<ruby><rb>...</rb><rt>...</rt>...
<ruby><rb>...<rt>...
<ruby>...<rt>...</rt>...
```

See https://github.com/w3c/webvtt/issues/264

Received on Friday, 21 October 2016 10:14:34 UTC