Draft: Add support for defining ticky tickers in Core
This allows the user to define new ticky tickers via a new Core Tickish
type, TickyCtr
. These behave like source notes in the sense that they
try to interfere minimally with simplification. It is intended that they
be introduced by Core-to-Core plugins late in the Core pipeline.
To-do:
-
Add test via a plugin to exercise the feature.