[whatwg] Corrections for examples in section 3.14.10

[Ivo Emanuel Gonçalves]

For those not aware of what issue this thread is discussing, Xiph is
implementing a set of file extensions to make sure implementations
work as well as possible with different content encapsulated in Ogg.

Those are:
.ogx for applications
.ogv for video
.oga for audio

Ogg files should use those file extensions with a notice that there is
a requirement (for the first) and a recommendation (for the other two)
that those files carry an Ogg Skeleton bitstream.  Ogg Skeleton is an
extension of Ogg to make it easier for implementations to demux
content inside Ogg containers.

However, as Ralph Giles mentioned, this is not entirely the case with
Vorbis and Speex.  If those codecs go alone in the container without
the Skeleton bitstream, which has been the behavior for the past years
since their conception they should use their legacy file extensions
(.ogg and .spx respectively) to make sure backwards-compatibility is
not broken.  This is then the desired way to serve those files and why
I proposed the corrections in the original post of this thread.

Nothing prevents files or implementations dealing with Vorbis and
Speex to use .oga, as long as the Skeleton recommendation is noticed
and .oga is not used as the default extension of those two codecs.

Any other type of data encapsulated in Ogg, multiplexed or not, should
use the new set of extensions.

I hope this information was useful.

-Ivo