AFFECTS line should contain portcategory/portname

so that automated tools can parse it as easily as possible, according to
Porter's handbook 11.2.1 [1].

[1] https://www.freebsd.org/doc/en/books/porters-handbook/moved-and-updating-files.html

PR: 241169
Submitted by: Yuichiro NAITO <naito.yuichiro@gmail.com>
Approved by: portmgr blanket