When custom categories are used in older versions, raco setup will
report a warning, but the documentation will still appear under the
Miscellaneous section. Thus, this is a backwards compatible
implementation of the idea.
find-relative-path expects a simple-form-path, but according to the documentation PLTUSERHOME as propagated by find-user-pkgs-dir must only be a complete-path?
Without this building of the documentation fails if PLTUSERHOME contains ".."