Interactive help
The finesse.help() function accepts either a string or object as input and will
show corresponding help. If a string is provided, it is assumed to be a KatScript
path like m, beamsplitter, or bs.T. Command names such
as xaxis are also supported.
This operates similarly to the Python built-in function help(): either a pager is
opened (if using a console; use PgUp and PgDn to navigate, and
q to escape) or the help text is printed (if using a notebook).