wp_count_comments() and get_comments_count() both do SQL queries

[markjaquith]

wp_count_comments() and get_comments_count() are similar functions, with a few differences:

• Their results are returned in different formats:
  • wp_count_comments() returns an array of:
    • spam
    • approved
    • moderated
    • total_comments
    • trash
    • post-trashed
  • get_comment_count() returns an array of:
    • spam
    • approved
    • awaiting_moderation
    • total_comments
• wp_count_comments() caches, but get_comment_count() always hits the database.
• get_comment_count() is used nowhere in WordPress core.

I propose that we add 'trash' and 'post-trashed' reporting to get_comment_count(), and then have wp_count_comments() use get_comment_count() instead of doing its own SQL queries.

See #6884 and #19901