Download Apple developer documentation as PDF files
Whatever be the reason, Apple has stopped providing PDF copies of most of it's Developer Documentation.

This won't work for all pages, but for your specific document, a PDF copy definitely used to exist (shown by this answer on SO).

The PDF itself is no longer available from Apple servers, but a quick Google search brought up this archived copy on CiteSeerX.

Whether you trust it is not modified or edited in any way is up to you (VirusTotal seems to say it's safe).