In an attempt to phase out the std::num::strconv module's string formatting
functionality, this commit reimplements some provided methods for formatting
integers on top of format!() instead of the custom (and slower) implementation
inside of num::strconv.
Primarily, this deprecates int_to_str_bytes_common
This implements all traits inside of core::num for all the primitive types,
removing all the functionality from libstd. The std modules reexport all of the
necessary items from the core modules.
Exposing ctpop, ctlz, cttz and bswap as taking signed i8/i16/... is just
exposing the internal LLVM names pointlessly (LLVM doesn't have "signed
integers" or "unsigned integers", it just has sized integer types
with (un)signed *operations*).
These operations are semantically working with raw bytes, which the
unsigned types model better.
This commit uniforms the short title of modules provided by libstd,
in order to make their roles more explicit when glancing at the index.
Signed-off-by: Luca Bruno <lucab@debian.org>