Render a generator spec back to T source
Inspects the gen Dict (as built by prop_gen_int,
prop_gen_df, …) and returns the T source that rebuilds a behaviorally
equivalent generator: both produce identical values under the same seed.
Closure-carrying generators (prop_map_gen, prop_such_that, prop_gen_fn)
and unknown generator kinds cannot be rendered and raise an error.
Dict): A generator spec (see
prop_gen_int, prop_gen_df, …).T source that rebuilds the generator.
prop_show_spec(prop_gen_int_range(0, 100))
# "prop_gen_int_range(0, 100)"