fullContainerDeclComponents

fn fullContainerDeclComponents(tree: Ast, info: full.ContainerDecl.Components) full.ContainerDecl {
    var result: full.ContainerDecl = .{
        .ast = info,
        .layout_token = null,
    };

    if (info.main_token == 0) return result; // .root
    const previous_token = info.main_token - 1;

    switch (tree.tokenTag(previous_token)) {
        .keyword_extern, .keyword_packed => result.layout_token = previous_token,
        else => {},
    }
    return result;
}