Document whether numpy.split() works in place

[felixdivo]

It should be documented whether numpy.split() works in place or not. I think it does not, but in general that information is probably easy to add for you maintainers.

Numpy/Python version information:

1.17.0 3.6.8 (default, Jan 14 2019, 11:02:34)
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]]

[seberg]

It returns views into the original array, the documentation could indeed spell that out a bit more clearly, by mentioning the word view somewhere probably, sub-arrray is not a well defined term in this regard, I guess.
Do you want to make a PR with a suggestion?

[felixdivo]

Yes, I opened the PR shown above.