The existence of hashmap_free() and hashmap_free_entries() confused me,
and the docs weren't clear enough. We are dealing with a map table,
entries in that table, and possibly also things each of those entries
point to. I had to consult other source code examples and the
implementation. Add a brief note to clarify the differences. This will
become even more important once we introduce a new
hashmap_partial_clear() function which will add the question of whether
the table itself has been freed.
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>