4ef06b4f2b Remove ToU64 from rustdocs (Tobin C. Harding)
Pull request description:
The `ToU64` trait is not meant to be used publicly, remove the mention of it from rustdocs.
ACKs for top commit:
shinghim:
ACK 4ef06b4f2b
apoelstra:
ACK 4ef06b4f2b9945b46c190abd0cb3a6dfe234c7b5; successfully ran local tests
Tree-SHA512: e9acef9194cee380aa2aa44af9285d4f6e025bdf09f76e5066916c51215db15f1f920fd8ecf3cf079f0a2dddab0332b3a7df104f5bd61d12fc337b4ed163310c