Add ability to convert a simple message to SelectExpression

[bugzilla-to-github]

This issue was created automatically by a script.

Bug 1394110

Bug Reporter: @Pike CC: @mathjazz, @merike, @zbraniecki See also: https://bugzilla.mozilla.org/show_bug.cgi?id=1423529 See also: https://github.com/mozilla/voice-web/issues/2159

If one forgets to enter a full plural form when translating a string, pontoon (rightfully) creates a single string.

Then it's hard to go back to an actualy pluralized string.

This also covers the scenario where en-US didn't have a plural form to begin with, say in a case where it knows that it's always a number greater than one.

[bugzilla-to-github]

Comment Author: @mathjazz

*** Bug #1406571 has been marked as a duplicate of this bug. ***

[bugzilla-to-github]

Comment Author: @mathjazz

Made the title more generic.

[bugzilla-to-github]

Comment Author: @Pike

Just came across https://github.com/mozilla/voice-web/issues/2159.