port/port.tcl: Document depends: and depends_*: from https://trac.macports.org/changeset/37909
port/port.tcl:
Document depends: and depends_*: from https://trac.macports.org/changeset/37909

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@38033 d073be05-634f-4543-b044-5fe20cf6d1d6

macports/macports-base,neverpanic/macports-base,danchr/macports-base,neverpanic/macports-base,macports/macports-base,danchr/macports-base