Example scenario:
Before this commit, the original note A never gets its next link persisted to disk.
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VUPAAFJL3JDSTGMBJMJUNT4EHFEL73Y5S4BEJZMFLNZUKNKWHGAAC
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V6JHPHYNDGOBF3OKHPYJ6IQEU5PSLWNUCQBGVW4TG7TYL6OLF3QAC
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F7JBFZFRALHRUTYYHJ2J7OBBB5WYPJBDTLDLZAMTVC3FUVJ7MAIAC
ZU3HJ6NH26LFY2NWRCCRMXECNEPVR25OJNOFEK5XJ3KYFJUCKQXAC