Clarify the distinction between $F$ and $1/M$ in transport properties

[tovrstra]

The following pages should explicitly show the definitions of $F$ and $1/M$ in the expression for the transport property:

• https://molmod.github.io/stacie/properties/shear_viscosity.html
• https://molmod.github.io/stacie/properties/bulk_viscosity.html
• https://molmod.github.io/stacie/properties/thermal_conductivity.html
• https://molmod.github.io/stacie/properties/electrical_conductivity.html
• https://molmod.github.io/stacie/properties/diffusion_coefficient.html

Because $M$ is in general the number of (independent) input sequences, it would be good to introduce a symbol $M_1$ or something similar for the number of inputs from a single MD run.