Fix template userdata append docs (#329)

* Fix template userdata append docs

* note on multipart

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

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Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>
Co-authored-by: Abhishek Kumar <abhishek.mrt22@gmail.com>
1 file changed