renderDocComments

fn renderDocComments(r: *Render, end_token: Ast.TokenIndex) Error!void {
    const tree = r.tree;
    // Search backwards for the first doc comment.
    if (end_token == 0) return;
    var tok = end_token - 1;
    while (tree.tokenTag(tok) == .doc_comment) {
        if (tok == 0) break;
        tok -= 1;
    } else {
        tok += 1;
    }
    const first_tok = tok;
    if (first_tok == end_token) return;

    if (first_tok != 0) {
        const prev_token_tag = tree.tokenTag(first_tok - 1);

        // Prevent accidental use of `renderDocComments` for a function argument doc comment
        assert(prev_token_tag != .l_paren);

        if (prev_token_tag != .l_brace) {
            try renderExtraNewlineToken(r, first_tok);
        }
    }

    while (tree.tokenTag(tok) == .doc_comment) : (tok += 1) {
        try renderToken(r, tok, .newline);
    }
}