This PR corrects warnings and errors discovered by podchecker. I've split up the fixes quite thinly so that the individual commits can be cherry picked as required. If you have any questions or comments concerning the PR, please just let me know! The PR is intended to be helpful, so if anything needs to be changed, then I will happily update it and resubmit.
`podchecker` noticed a type mismatch in the item list altered in this
change. The reason being that the first item, "-1", as an argument to
`=item` is interpreted by POD formatters as a definition section, whereas
the second item, "0", is interpreted as a number. The solution presented
here removes the item list, reduces the amount of text and reflects a
similar text segment in the POD of the following section (the docs for
`openpage()`). This change thus tries to remain consistent with the current