Add matrix_icon shortcode for inline emoji-sized Matrix icon

[ayush-gupta18-hub]

Description

Adds a reusable Zola shortcode named matrix_icon that renders the existing
favicon SVG inline at emoji-size (1em), so it aligns consistently with text
and other emoji-sized icons.

This makes it easier to include the Matrix icon inline in content without
having to insert or manually resize image assets.

The shortcode loads the favicon SVG and wraps it in a small styled span to
ensure consistent size and vertical alignment.

Usage: {{ matrix_icon() }}

Note: While working on this, I confirmed that the site is built with Zola
rather than Hugo, so the helper is implemented as a Zola shortcode.

Related issues

Fixes #3106

Role

Individual contributor

Timeline

No specific deadline — review at your convenience

Signoff

Please sign off your individual commits or whole pull request.
All commits in this PR are signed off.

[ayush-gupta18-hub]

hey @MTRNord could you please review my PR and tell me if any changes are needed and would love to get feedback from your side

[MTRNord]

#3125 was merged instead. Thanks for the contribution. You can have a look at #3125 (review) to learn why I chose that one over this PR. :)

Also for the next time make sure to follow https://github.com/matrix-org/matrix.org/blob/main/CONTRIBUTING.md#sign-off without this step we would have not been able to accept this PR.

[ayush-gupta18-hub]

Thanks for reviewing my PR and for the feedback
I’ll review the other PR to understand the improvements and learn from the approach that was merged.
I’ve also taken note of the sign-off requirements and will make sure to follow the CONTRIBUTING guidelines correctly in future contributions.
can you please tell me if there is any community discussion channel? it would be of great help

[MTRNord]

can you please tell me if there is any community discussion channel? it would be of great help

Yes we have a matrix channel available at https://matrix.to/#/#matrix.org-website:matrix.org