TrackChanges: problems with typing in Japanese

problem:

Typing japanese (e.g. with Anthy) does not work when the TrackChange-Plugin is activated.

Exceptions (= where it DOES work):

• Ubuntu: Google Chome
• Windows: Edge

Example "ha":

• when it works, typing "h" does not show any change in the content until the "a" is typed, too.
• when is does NOT work, typing "h" results in the character "h" being inserted in the segment right away.

solution:

After some basic changes (see TRANSLATE-1778 also), typing in Japanese now works for:

• Windows: Chrome, Edge, Firefox (IE11 also, but IE11 can't do SpellCheck)
• Linux: Chrome, Firefox