Improved description for azd-templates

[puicchan]

Please confirm this pull request meets the following requirements:

• [x] I followed the contributing guidelines: https://github.com/github/explore/blob/main/CONTRIBUTING.md.
• [x] I have no affiliation with the project I am suggesting (as a maintainer, creator, contractor, or employee).

Which change are you proposing?

• [x] Suggesting edits to an existing topic or collection
• [ ] Curating a new topic or collection
• [ ] Something that does not neatly fit into the binary options above

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Editing an existing topic or collection

I'm suggesting these edits to an existing topic or collection:

• [ ] Image (and my file is *.png, square, dimensions 288x288, size <= 75 kB)
• [x] Content (and my changes are in index.md)

Since azd is the command-line utility for invoking the Azure Developer CLI, including azd will make things clearer.

Curating a new topic or collection

• [ ] I've formatted my changes as a new folder directory, named for the topic or collection as it appears in the URL on GitHub (e.g. https://github.com/topics/[NAME] or https://github.com/collections/[NAME])
• [ ] My folder contains a *.png image (if applicable) and index.md
• [ ] All required fields in my index.md conform to the Style Guide and API docs: https://github.com/github/explore/tree/main/docs

Please replace this line with an explanation of why you think this topic or collection should be curated.

Something that does not neatly fit into the binary options above

• [ ] My suggested edits are not about an existing topic or collection, or at least not a single one
• [ ] My suggested edits are not about curating a new topic or collection, or at least not a single one
• [ ] My suggested edits conform to the Style Guide and API docs: https://github.com/github/explore/tree/main/docs

Please replace this line with an explanation of your proposed changes.

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