`rcount` and `ccount` for `plot_surface()`

As of v2.0, mplot3d's :func:`~mpl_toolkits.mplot3d.axes3d.plot_surface` now

accepts `rcount` and `ccount` arguments for controlling the sampling of the

input data for plotting. These arguments specify the maximum number of

evenly spaced samples to take from the input data. These arguments are

also the new default sampling method for the function, and is

considered a style change.

The old `rstride` and `cstride` arguments, which specified the size of the

evenly spaced samples, become the default when 'classic' mode is invoked,

and are still available for use. There are no plans for deprecating these

arguments.