Additional Japanese language requirements for IMSC (1.2?)

[nigelmegitt]

Three Japanese language-related issues were recently raised for IMSC vNext requirements. They may also be relevant to other languages. Opening a tracking issue here:

• Consider adding tts:fontShear w3c/imsc-vnext-reqs#43
• Consider allowing an author to specify tts:textcombine if characters are to be scaled to fit within 1 em w3c/imsc-vnext-reqs#44
• Consider adding a solution for ruby overhang problem w3c/imsc-vnext-reqs#45

We need to decide whether to tackle each of these in IMSC 1.2 or a later iteration of IMSC.

[himorin]

these requests are postponed to next: https://www.w3.org/2020/03/05-tt-minutes.html#x02