Function: ibut:label-to-key
ibut:label-to-key is a function alias for hbut:label-to-key, defined
in hbut.el.
Signature
(ibut:label-to-key LABEL)
Documentation
Normalize LABEL for use as a Hyperbole button key and return key.
Eliminate any fill prefix in the middle of the label, replace _ with
__, remove leading and trailing whitespace and replace all other
whitespace sequences with _.