Unvendor pydoc_data and _pydecimal. ### Description

Removes / unvendors some python modules:

- Remove `_aix_support.py`, which is for supporting IBM AIX OS.

- Unvendor `_pydecimal.py`.
  - _pydecimal is a pure Python implementation of `decimal` module. [Importing `decimal` fallbacks](https://github.com/python/cpython/blob/main/Lib/decimal.py) to `_pydecimal` if the C-implementation `_decimal` is not available. In our case, _decimal is available, so _pydecimal will not be normally used. 

- Unvendor `pydoc_data`.
  - pydoc_data contains [a large (~700KB) dictionary](https://github.com/python/cpython/blob/main/Lib/pydoc_data/topics.py) for explaining python builtins. This is mostly used when `help("...")` is called.

### Checklists

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests
- [x] Add new / update outdated documentation

from pathlib import Path

import typer

from ..pyzip import create_zipfile


def main(
    libdir: Path = typer.Argument(
        ..., help="Path to the directory containing the Python standard library."
    ),
    pycompile: bool = typer.Option(
        False, help="Whether to compile the .py files into .pyc."
    ),
    output: Path = typer.Option(
        "python.zip", help="Path to the output zip file. Defaults to python.zip."
    ),
) -> None:
    """
    Bundle Python standard libraries into a zip file.
    """
    create_zipfile(libdir, output, pycompile=pycompile, filterfunc=None)
    typer.echo(f"Zip file created at {output.resolve()}")


main.typer_kwargs = {"hidden": True}  # type: ignore[attr-defined]

from pathlib import Path

import typer

from ..pyzip import create_zipfile


def main(
    libdir: Path = typer.Argument(
        ..., help="Path to the directory containing the Python standard library."
    ),
    pycompile: bool = typer.Option(
        False, help="Whether to compile the .py files into .pyc."
    ),
    output: Path = typer.Option(
        "python.zip", help="Path to the output zip file. Defaults to python.zip."
    ),
) -> None:
    """
    Bundle Python standard libraries into a zip file.
    """
    create_zipfile(libdir, output, pycompile=pycompile, filterfunc=None)
    typer.echo(f"Zip file created at {output.resolve()}")


main.typer_kwargs = {"hidden": True}  # type: ignore[attr-defined]
