docs: add missing search path in containers-registries.conf(5)

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

Author: Luap99

image/docs/containers-registries.conf.5.md

@@ -21,6 +21,7 @@ In addition to registries.conf, drop-in files using the same format from the fol
  - `/etc/containers/registries.rootful.conf.d` (only when running as uid 0)
  - `/etc/containers/registries.rootless.conf.d` (only when running as uid > 0)
  - `/etc/containers/registries.rootless.conf.d/$UID` (only when running as uid > 0)
+ - `/usr/share/containers/registries.conf.d`
  - `/usr/share/containers/registries.rootful.conf.d` (only when running as uid 0)
  - `/usr/share/containers/registries.rootless.conf.d` (only when running as uid > 0)
  - `/usr/share/containers/registries.rootless.conf.d/$UID` (only when running as uid > 0)