plot_diet_comp1() is an alias of plot_diet_comp(): it produces the
predator-age x prey-age bubble grids (observed / estimated / Pearson residual)
for each predator-prey-year interaction. It is provided as a named entry point
alongside plot_diet_comp2() (the aggregation-aware line / bar / bubble plots)
for scripts that call both by name.
Value
Invisibly returns a list of the printed plot grids (see
plot_diet_comp()).