Allows some simple post-processing on boolean values.
The following are the list of keys which this supplier will return a value for.
[true value]/[false value]
This key is of the format "true/false", with the text before the '/' returned if the boolean is true and the text after the '/' returned if it is false. Example values:
(Since 2.0.0) Returns the negated (or opposite) value of the boolean. e.g.: 'true' will become 'false'.