fix typo

(8) An example for using one set of per-chunk values (dipole moment

vectors) for molecule chunks, spreading the values to each atom in

each chunk, then defining a second set of chunks as spatial bins, and

using the "fix ave/chunk"_fix_ave_chunk.html command to calulate an

using the "fix ave/chunk"_fix_ave_chunk.html command to calculate an

average dipole moment vector for each bin.  This example is explained

on the "compute chunk/spread/atom"_compute_chunk_spread_atom.html

command doc page.