Go provides

    • C-style /* */ block comments
    • and C++-style // line comments.

    godoc

    Every package should have a package comment, a [block] comment preceding the package clause.
    For multi-file packages, the package comment ONLY needs to be present in one file, and any one will do.

    Inside a package, any comment immediately preceding a top-level declaration serves as a doc comment for that declaration.
    Every exported (capitalized) name in a program should have a doc comment.