Solve the uneven distribution situation that has been present for
picking random rumors for a long time and for random engravings,
epitaphs, and hallucinatory monster names since 3.6.0. This relies
on the previous partial solution where short lines have been padded
to a longer length. When that length is N and random seek lands in
a long line of length L, retry if the position is in the first L-N
characters. Put differently, it if takes more than N characters to
reach the next newline, reject that random seek and try again. This
effectively makes long lines behave as if they had the same length
of N as the short lines have been padded to and when all lines are
the same length, all entries have the same chance to be chosen.