docs: fix typedoc warnings and outdated tsdoc comments

[sripwoud]

Generating the docs produce some warning:
yarn docs

[info] Converting project at ./packages/core
[warning] No entry points were provided, this is likely a misconfiguration.
[info] Converting project at ./packages/data
[info] Converting project at ./packages/group
[warning] The signature Group.import has an @param with name "nodes", which was not used.
[info] Converting project at ./packages/heyauthn
[info] Converting project at ./packages/identity
[info] Converting project at ./packages/proof
[info] Converting project at ./packages/utils
[warning] The signature getDeployedContract has an @param with name "The", which was not used.
[info] Merging converted projects
[info] Documentation generated at ./docs