Use ngettext-style internationalization for strings with plurals

[progval]

Description

Currently, pluralizable strings look like %d channel(s) cleared, and %d channel(s) dropped.; or %d canau(x) vidé(s) et %d canau(x) supprimé(s). in French.

Whereas correct pluralization handling would allow conditionally having s (or the locale's equivalent) only when needed.

Why this would be useful

It is much more readable