docs: add usage examples for generate_guideline_templates.py

[outlookenjoyer]

Closes #407

Added usage instructions and examples to the "Writing a guideline locally" section in CONTRIBUTING.md.

This includes:

• How to run the --help command
• Examples of generating templates with specific flags (e.g., configuring the number of compliant/non-compliant examples and adding bibliographies)
• An example of generating multiple templates at once

This should make it much easier for new contributors to use the script without needing to read the source code

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[plaindocs]

This looks good.

I've actually suggested removing the section entirely over in #417 if we really don't want people generating guidelines locally, but if we're happy leaving that it's better to have some docs.

I suspect we could remove the multiple templates at once though.

[outlookenjoyer]

@plaindocs Thanks for the feedback! I've resolved the merge conflicts and kept my changes. I've also removed the section about generating multiple templates as you suggested.

Could you please take another look? If everything is okay now, are you ready to merge this PR?

[plaindocs]

Looks good.

One simplification suggested.

Hopefully updating from main will fix the FLS error

[plaindocs]

Suggested change

	We have a script `./generate_guideline_templates.py` which assumes you're using `uv` that can be run to generate the template for a guideline with properly randomized IDs.
	Use `./generate_guideline_templates.py` to generate a guideline template with properly randomized IDs. You'll need to `uv` to install the dependencies.

[outlookenjoyer]

Done! Also merged main to branch