[InterNetNews/inn] f39ed7: libinn: Document Cancel-Lock functions

[Julien ÉLIE]

  Branch: refs/heads/main
  Home:   https://github.com/InterNetNews/inn
  Commit: f39ed7175b7eab9bb024c09ceed1f0c1c28a455e
      https://github.com/InterNetNews/inn/commit/f39ed7175b7eab9bb024c09ceed1f0c1c28a455e
  Author: Julien ÉLIE <Julien-Elie at users.noreply.github.com>
  Date:   2022-02-18 (Fri, 18 Feb 2022)

  Changed paths:
    M doc/pod/libinn.pod

  Log Message:
  -----------
  libinn: Document Cancel-Lock functions

Several functions were recently added, with no related documentation
in libinn(3).  Now that this man page is in POD format, it is much
easier to add that documentation.

see #47