Add links to NCCL docs from GB docs

Author: msimberg

docs/guides/gb2025.md

@@ -86,3 +86,7 @@ Without these settings, we have observed application slowdown due to poor thread
 
 !!! todo
     write a guide on which versions to use, environment variables to set, etc.
+
+See [the container engine documentation][ref-ce-aws-ofi-hook] for information on using NCCL in containers.
+The [NCCL][ref-communication-nccl] contains general information on configuring NCCL.
+This information is especially important when using uenvs, as the environment variables are not set automatically.