(doc) Remove incorrect line about extensions

[gep13]

Description Of Changes

Remove line from the guide about creating Extension packages, as it is incorrect.

Motivation and Context

The .extension file extension is a requirement when creating extension packages. It is this file extension that causes Chocolatey CLI to extract the files into the extensions folder, in the same way that the .hook file extension that causes files to be extracted into the hooks folder, and then the .template file extension that causes files to be extracted into the templates folder.

Testing

• I have previewed these changes using the Docker Container or another method before submitting this pull request.

Change Types Made

• Minor documentation fix (typos etc.).
• Major documentation change (refactoring, reformatting or adding documentation to existing page).
• New documentation page added.
• The change I have made should have a video added, and I have raised an issue for this.
  • Issue #

Change Checklist

• Requires a change to menu structure (top or left-hand side)/
• Menu structure has been updated

Related Issue

N/A

[AdmiringWorm]

LGTM

[AdmiringWorm]

LGTM