Revert "Remove references to this.$"
Revert "Remove references to this.$"

Unfortunately we never had deprecation warnings for this,
and it seems it is still being referenced.

This reverts commit ab745acdc2cc3bedce08711190d91370c2cc593b.

Change-Id: I44f1b8d9534b32df7642c61cb2e7b6f95d52b57e

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui