Should delta_t dtype be numeric?

[AdamRJensen]

@kandersolar could you comment on this?

[kandersolar]

Right now it is documented as "float or array": https://github.com/search?q=repo%3AAssessingSolar%2Fsolposx%20delta_t&type=code

numeric would also include Series? Fine with me, I see no reason not to

[AdamRJensen]

Related to pvlib/pvlib-python#2525