Clean up for 12/20/2021 content update

[Gregory Hecht]

This week's update added Book #4 to the title Official Index to the Marvel Universe.  I'm not sure what this book is (there is no scan).  The full contents of the periodical issues are collected in the already listed Books #1, #2, and #3.  As far as I know, there was never any collection of the entire series into a single volume, and certainly not at the same cover price as the already listed Books #1, #2, and #3.  

My guess is that this might be some sort of entry to cover one of the other Official Index to the Marvel Universe titles, but AFAIK all of those are already in the database.  My recommendation is that the new Book #4 should be deleted.