add method pynext(x, d)

[cjdoris]

No description provided.

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	7d17246...	main / 7d17246...
basic/@py/pydict/init	0.249 ± 0.066 ms	0.248 ± 0.051 ms	1.01 ± 0.34
basic/@py/pydict/pydel	0.25 ± 0.032 ms	0.253 ± 0.027 ms	0.986 ± 0.16
basic/julia/pydict/init	0.223 ± 0.063 ms	0.223 ± 0.07 ms	1 ± 0.42
basic/julia/pydict/pydel	0.23 ± 0.036 ms	0.229 ± 0.049 ms	1 ± 0.27
gc/full	0.61 ± 0.0075 s	0.607 ± 0.023 s	1 ± 0.04
time_to_load	2.07 ± 0.021 s	2.06 ± 0.059 s	1.01 ± 0.03

Memory benchmarks

	main	7d17246...	main / 7d17246...
basic/@py/pydict/init	5.01 k allocs: 0.0764 MB	5.01 k allocs: 0.0764 MB	1
basic/@py/pydict/pydel	5.01 k allocs: 0.0764 MB	5.01 k allocs: 0.0764 MB	1
basic/julia/pydict/init	4.01 k allocs: 0.0612 MB	4.01 k allocs: 0.0612 MB	1
basic/julia/pydict/pydel	4.01 k allocs: 0.0612 MB	4.01 k allocs: 0.0612 MB	1
gc/full	0 allocs: 0 B	0 allocs: 0 B
time_to_load	0.143 k allocs: 10.6 kB	0.143 k allocs: 10.6 kB	1