Building a did:key document with a publicKeyJwk

Dear all,

I am building a did:key document. The base64url for multibase puts a u
prefix in front. In my publicKeyJwk I keep the prefix for the x and y
coordinates of the key. I've attached some scratch code.

https://gist.github.com/bshambaugh/0996f89023b54aababe1d5ff48a6ca2b

Would it be correct, or incorrect to remove the prefix? I am not sure what
to make of RFC7518.
Perhaps since the example with P-256 https://w3c-ccg.github.io/lds-jws2020/
is missing the
prefix u from https://github.com/multiformats/multibase I need to remove
it.

Thanks,

Brent