Update transfer_sd.md

[wzr1337]

Adding an "expansion" guide

[suchmememanyskill]

Just reading through the changes, have not seen it live

• i think the header is not specific enough. May want to explicitly mention it uses direct disk/partition cloning
• i think the final step can be left out
• This is missing a step. After cloning the partitions and copying the files, sd:/emummc/emummc.ini will contain a misalligned emummc sector offset. You need to fix this by going to hekate > emummc > migrate emummc > fix raw