Duplicate documentation entry includes unreproducible xdg_cache_home value

I see that in ba91de93 there is an attempt to make isbg reproducible by "forcing" a determinstic value of the xdg_cache_home value in the isbg.isbg module via using a autodata annotation. However, in Debian sid (as of 20200313) this appears to make two entries appear, one with the fixed value you specify in ba91de93 and one with the original, regrettably, unreproducible value: