Pass a relevant number of unread notifications to the messages
'echo-mark-all-as-read' and 'echo-mark-wiki-as-read' each time
they are used, in order to facilitate the use of PLURAL in
the messages. This allows translators to say e.g. "mark both as
read" when there are two unread notifications, for instance.
Bug: T321462
Change-Id: Ida65be2d7f2663d9802f71c7ea1eb588db8cd254
The loop accidentally overwrote the whole array in every iteration.
It's not necessary to define these empty arrays at all: when working
with multi-dimensional arrays, PHP will create them as needed.
Follow-up to 4835b6b1cb.
Bug: T323491
Change-Id: I5043efc31722d2b9cd2a8dd482594355a761008e
