It seems redundant in most contexts, e.g. `use plonky2::field::extension_field::Extendable;`. One could import `extension_field`, but it's not that common in Rust, and `field::extension` is now about as short.
* Complete versions of rotate left and shift left.
* Implement rotate/shift right.
* cargo fmt
* Fix documentation.
* Reduce visibility of helper functions.
* Address Jaqui's PR comments.
* Disable fall-through check as the run test assumes no failure here.
* Try to fix doctest failure.
* First draft of bitwise AND.
* Refactor everything; add support for other binary bitops.
* Documentation; fix integration into rest of ALU.
* Allow `cargo fmt` to make code harder to read.
* Refactor following Jakub's suggestions.
* Fix variable name.
* Minor documentation.
* Basic tests.
* Address Daniel's PR comments.
* Remove the 'BIT' prefix from the BIT{AND,IOR,XOR,ANDNOT} names.
* cargo fmt/clippy
* Simplify bit test.
