git: openjdk/amber-docs: Minor nit

[duke]

Changeset: 11c2a618
Branch: master
Author:    Gavin Bierman <gavin.bierman at oracle.com>
Date:      2025-06-20 18:20:16 +0000
URL:       https://git.openjdk.org/amber-docs/commit/11c2a618cf24fd423261468717c7d88ef30356d1

Minor nit

! site/_index.md