* Introduces `compression` package for https://peps.python.org/pep-0784/
This commit introduces the `compression` package, specified in PEP 784
to re-export the `lzma`, `bz2`, `gzip`, and `zlib` modules. Introduction
of `compression.zstd` will be completed in a future commit once the
`_zstd` module is merged.
This commit also moves the `_compression` private module to
`compression._common._streams`.
* Re-exports existing module docstrings.
Emma Smith