Fix broken link for feature request guidance

[mccoyp]

Description

This fixes a failing nightly pipeline by removing a link to a now-removed doc. The gist of the guidance is instead referenced directly.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull Request Overview

This PR fixes a broken documentation link that was causing a nightly pipeline failure. The change removes a reference to a deleted guidance document and replaces it with inline text that directly explains the feature request process for Python SDKs.

Key changes:

• Replaced broken link reference with inline guidance text explaining the REST API-based feature request process
• Removed unused link definition and unnecessary horizontal rule separator