Indicate which string fields/options are multibase

[lidel]

Problem

https://github.com/ipfs/go-ipfs/pull/8183 introduced a breaking change where pubsub topic name is expected to be a multibase string, but the type of the field remains to be string.

ipfs-docs/http-api-docs reads go-ipfs sources and generates docs like https://docs.ipfs.io/reference/http/api/#api-v0-pubsub-sub which are EXTRA confusing – reader may asume those are strings in cleartext, not bytes represented as multibase (that usually happen to be a valid string):

Solution

Find a way to indicate those fields are multibase (new type? additional metadata?), and then update ipfs-docs/http-api-docs to surface that info in produced HTML.