Remove a commented section about pkg_ from the ports chapter in the handbook

[bcr]

Summary

I'm preparing a translation of the ports chapter for the german handbook using the new gettext tools. I want to remove that section before starting to reduce the overall number of strings, although I think gettext will filter them out. The commented section only contains legacy descriptions about pkg_* tools. I don't think that we ship any release of FreeBSD with pkg_* tools and since that section is commented out anyway, no one will miss it. In case they do, there's always the revision history available.

We should probably make a similar sweep over the handbook and check other commented sections to see whether we still need them or if they need work to be uncommented.

Test Plan

1. Apply the patch to the handbook
2. Compile the handbook
3. Nothing is missing or added afterwards, just the source has been reduced by a bunch of lines ;-)