mutt:master commits

Fix a couple small formatting issues.

The nelem attribute name is a bit vague. When I add a counter for the "total entries" in the next commit, it will be easy to get confused. So rename it to bucket_count, which I hope is clear.

Track the total number of elems in the hash table. Increment/decrement hash elem_count on insert/removal.

Some of mutt's hashes are based on the size of the mailbox, with room to grow. Generally they perform okay. However, some of the hash tables are based on "Hmmmm... I think this should be enough in general" guesstimates, such as the label hash, or the auto_subscribe hash. When those guesses are wrong, it can degrade performance. So this commit allows the hash table to resize its...

Embed the DO_SORT() and the call to skip_duplicates() so I can understand it better. Then remove the duplicate call to mutt_buffer_printf(). It seems the sort is delayed until after any initial md entries without a header were first skipped, to make the sort faster. There could be a very small number of "new" entries with a header, and if they are not at the beginning this coul...