fix: docs url resolution

[JiyaGupta-cs]

Closes #443

This PR fixes incorrect resolution of extensionless documentation URLs linked from the templates site.
Links pointing to documentation pages under https://docs.accordproject.org/docs/ were resolving to the docs root instead of the intended pages when the .html extension was omitted.

Problem

The documentation site serves pages as static HTML files (e.g. started-hello.html, tutorial-nodejs.html).
However, several links originating from https://templates.accordproject.org reference extensionless URLs, such as:

/docs/started-hello
/docs/tutorial-nodejs

Since no clean URL resolution or redirect rules were configured, these URLs failed to map to an existing resource and instead redirected users to the documentation root.

Changes

Updated generated links to include .html.

Author Checklist

• Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• Vital features and changes captured in unit and/or integration tests
• Commits messages follow AP format
• Extend the documentation, if necessary
• Merging to master from fork:branchname