Renders global decorator labels and object-specific decorator groups
as sibling entries under a common prefix. Reuses format_tree_leaves()
for rendering children within object groups.
format_decorator_entries(decorators_info, prefix)(character(1)) Formatted string with tree connectors
(list) with global (character vector) and objects (named list) components,
as returned by format_decorators_tree()
(character(1)) Prefix for each line