Respect clicks docstring `\b` and `\f` markers

[deadnews]

\b:

https://click.palletsprojects.com/en/8.1.x/documentation/#preventing-rewrapping
Rewrapping can be disabled on a per-paragraph basis by adding a line with solely the \b escape marker in it.

\f:

https://click.palletsprojects.com/en/8.1.x/documentation/#truncating-help-texts
You can use the \f escape marker to have Click truncate the help text after the marker.

Ref: #57 and #58