In order to spell check, you just need to run this from anywhere in developer-docs:

pnpm spellcheck

If you want to add a new word to the dictionary, you should add the word to additional_dict.txt and then run sort -o additional_dict.txt additional_dict.txt.

Note that aspell, at least as it is configured now, does not support adding words with numbers in them, such as MultiEd25519. Instead, you'd just want to add MultiEd.

See the top level README.