Use {int}::to_le_bytes in WriteBytesExt

[bushrat011899]

Objective

WriteBytesExt currently uses a hand-rolled bit-shifting algorithm to divide and conquer unsized integers into little-endian bytes, before passing them to Write::write_all. While the implementation is correct, core provides {int}::to_le_bytes, which may optimise better (since it more clearly conveys intent to the optimiser), and is definitely more likely to be tested and maintained.

Solution

• Switched to {int}::to_le_bytes for the implementations of WriteBytesExt::write_le

[bushrat011899]

Like #203, I can't replicate the CI failure locally. Any ideas?

[bushrat011899]

See #206 for CI failure cause and possible fix.