Singular/plural items could use a "copy from singular/plural" button

[xibe]

The current "Copy from original" is certainly useful, but in the case singular/plural items, a button to copy from the other form would have huge usability improvement.

Singular and plural forms are most of the time very much alike, and share many of their words. With such a button, a click and the translator would just have to modify the form to turn it into the other form (adding the 's' or any language-specific way).

Ideal, each form would have its own "Copy from [other form]" button.