The current CONTRIBUTING.md is missing initialization of Git Submodule `cpython`

[leftkats]

/type documentation

Which area/kind this task is related to?

/type documentation

Task Description

The current Contributing.md is missing a critical step for local environment setup, leading to build failures. Specifically, when following the current instructions, the cpython directory remains empty because it is a Git Submodule that is not initialized by default.

This causes pip install -r requirements.txt to fail since it cannot find the referenced file -r cpython/Doc/requirements.txt.

logs:

ERROR: Could not open requirements file: [Errno 2] No such file or directory: '/github/python-docs-el/cpython/Doc/requirements.txt'

Proposed Changes:

Option 1: Remote Requirements

If we only need the dependency list without the full CPython source code, we can point pip directly to the official raw file.

Update the first line of requirements.txt to:

-r https://raw.githubusercontent.com/python/cpython/3.14/Doc/requirements.txt

Option 2: Shallow Submodule Update

If we prefer to keep the submodule for strict version locking (at commit afaa3b0), we should use a shallow clone. This downloads only the current files (~100MB) instead of the entire history.

Update the CONTRIBUTING.md to submodule initialization to:

git submodule update --init --recursive --depth 1