fix bz55 - wrong plural for slice of cake

fix bz55 - wrong plural for slice of cake

Entered in bugzilla prior to release:  "slice of birthday cake" became
"slouse of birthday cake" when made plural.  "slice of pizza" used to
work, but adding an entry for "louse" <-> "lice" to one of the special
handling lists for singular/plural broke "slice" since only a trailing
substring match is performed for entries in that particular list.