explain new semantics for accessing pN for hybrid styles

example of ones that do are the "granular pair styles"_pair_gran.html

which calculate the tangential force between two particles and return

its components and magnitude acting on atom I for N = 1,2,3,4.  See

individual pair styles for details. When using hybrid pair styles,

these quantities are the combined lists of the individual quantities

for the pair styles active for a given pair of atom types padded with

zeros.

individual pair styles for details. When using pair style {hybrid},

the output will be that of the Nth quantity from the active sub-style

active or 0.0. The maximum allowed N is the maximum of any sub-style.

When using pair style {hybrid/overlay} all additional properties of

all pair styles are available for output, but the values of inactive

sub-styles for a given pair of atom types will be 0.0. Thus if there

are, for example, 3 sub-styles and 2 of them have additional output

(3 and 4 items, respectively), the maximum N would be 7 and {p1}, {p2},

and {p3} would refer to the first 3 additional properties and the

remaining allowed parameters {p4} to {p7} would address properties {p1}

to {p4} of the second sub-style with additional properties.

The value {dist} will be in distance "units"_units.html.  The value

{eng} will be in energy "units"_units.html.  The values {force}, {fx},

The output for {dist} will be in distance "units"_units.html.  The

output for {eng} will be in energy "units"_units.html.  The output for

{force}, {fx}, {fy}, and {fz} will be in force "units"_units.html.

The outpur for {pN} will be in whatever units the pair style defines.

The output for {pN} will be in whatever units the pair style defines.

[Restrictions:] none