[simple-ruby] Not all jukugo ruby is like group ruby

[r12a]

3.4 Placement of Jukugo-ruby
https://w3c.github.io/jlreq/docs/simple-ruby/#placement-of-jukugo-ruby

BP w3c/jlreq#2

If even a single ruby string is longer than its corresponding base character when laid out without inter-letter spacing, the processing is identical to group-ruby (see Figure 17 and Figure 18).

Not always, as described in JLREQ. If you have an example such as the following, my understanding is that there are limits to the amount of overlap allowed, which leads to gaps in the annotations (there would be no gaps for group ruby).

This seems like an oversimplification (which also doesn't help implementers understand how jukugo is different from mono- and group-ruby).

[frivoal]

This looks like an example of Jukugo processing for kata-tsuki ruby, but simple ruby only deals with naka-tsuki ruby. In that context, the proposed rule is still a simplification over the full range of possibilities, but a much less radical one.

[frivoal]

(also, the aspect of this issue that this is not specific to kata-tsuki ruby seems to be a duplicate, or at least a close relative of #4)

[r12a]

Closing as duplicate of #4.