I haven't found a way to add it to my schedule and priority list. As a rough estimate, doing a new edition is probably a month's worth of work spread out over three or four calendar months.

I'm guessing chromatic is waiting because he's very busy and the Perl 5 release cycle has sped up. It takes a long time to update and edit a book. The 4th edition of the book was published in October 2015 while Perl 5.24 was released in May 2016 and Perl 5.26 in May 2017.