Fix: Auto enable manual registration and enhance the docummentation

[youngeunkwon0405]

What does this PR do ?

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flowchart LR
    A[Pre-checks] --> B[PR Tests]
    subgraph Code Review/Approval
        C1[Expert Review] --> C2[Final Review]
    end
    B --> C1
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[youngeunkwon0405]

/ok to test aced81f

[ericharper]

@youngeunkwon0405 , can you fix the conflicts?

[youngeunkwon0405]

/ok to test dee1f75

[svcnvidia-nemo-ci]

🔄 Merge queue validation started!

You can track the progress here: https://github.com/NVIDIA/Megatron-LM/actions/runs/24793943617