[chore] Refresh docs/extending.md — Python skill example is stale

[lugassawan]

Type

• Documentation (README, catalog, SECURITY, etc.)

Surface

Files to change: docs/extending.md

Description

extending.md instructs contributors to copy skills/language-go/ to skills/language-python/ as the worked example, but skills/language-python/ already exists (shipped in PR #67). A contributor following this guide verbatim would hit a directory conflict immediately.

Current state: example target is language-python/ (already exists).
Desired state: example targets a non-shipped skill (e.g., language-ruby/ or language-<name>/) or is genericized.

Acceptance

• extending.md no longer references language-python/ as the copy target
• The example remains accurate — no reference to an already-existing skill directory

[Tiago-Vier-Preto]

Hey, can I work on this?

[lugassawan]

Hey, can I work on this?

Sure.