Tracking issue for slice_rotate

[scottmcm]

Implemented in #41670; merged 2017-06-02.

[mbrubeck]

I suggest renaming the method from rotate to rotate_left; otherwise I have trouble remembering exactly what it does either when writing code or when reading it. (If we do this, it would probably also be logical to add a rotate_right method.)

[scottmcm]

Bikeshed:

• rotate, following Stepanov and McJones, like in C++, also Ruby
• rotate_left+rotate_right
• bring_to_front, like in D
• slide, from Parent, fn(&mut [T], impl RangeArgument, usize) -> Range<usize> (often a nicer signature, but easy to implement using rotate on a subslice, so not necessarily the best primitive)

Edit: Added Ruby

[mbrubeck]

More comparison notes:

• collections.deque.rotate in Python rotates to the right
• rotate_left and rotate_right are used in Rust for bitwise rotation

[jethrogb]

The doc text links to non-free documentation. Can we find a publicly available source to link to?

[frewsxcv]

Opened a pull request for introducing rotate_{left,right}: #46777