Move const q under Constants

[KronosTheLate]

This PR moves the definition of the constant q under "Constants". See #556.

I also changed the comment on the line defining q from "e means 2.718..." to "avoid naming conflict with e", as I feel the original phrasing could be confused with the e in the line that means "times 10 to the power of..."

[sostock]

You only moved the definition of q. The definition of eV needs to be moved as well, since it uses q.

[KronosTheLate]

Nice catch @sostock. However, eV is not a constant, but a unit. So I will move it to under the "constants" section, right?

[j-fu]

Once you are working on the constants: are you aware of #545 ?

[KronosTheLate]

not at all

[sostock]

However, eV is not a constant, but a unit. So I will move it to under the "constants" section, right?

IMO, you can also move it into the constants section (right below q), since there are other units that are defined in that section as well (c, u).

[KronosTheLate]

That is not an argument to move eV into the constants section, but rather c and u out of it IMO.

[sostock]

That’s fine too, although I like that the units are defined immediately after the constants on which they are based.

[KronosTheLate]

There is sone appeal, but I personally look up the variables for constants all the time, and love having them all in one place. So that has more weight to me, as I frequently make use of it.