[PATCH 0/4] mark symbols that are unnecessarily public static

Over the years, refactoring various subsystems, adding new callers, and rewriting them from scratch, made some symbols that started as static into global, and some other symbols that started as global, no longer need to be visible outside a file that use them. Here is a small patch series that turns them back into file-scope static.

Honestly, I suspect that [3/4] was probably better with a forward declaration in the preview I sent earlier, but in the longer term, readers would not care if this conversion ended up in a large code movement, as they do not have to even know it.

 1/4: ident: remove unused author_ident_sufficiently_given()
 2/4: add -i: hide init/clear_add_i_state() functions
 3/4: read-cache: hide refresh_cache_entry()
 4/4: unpack-trees: hide verify_uptodate()

 add-interactive.c |  11 +-
 add-interactive.h |   9 --
 ident.c           |   5 -
 ident.h           |   1 -
 read-cache-ll.h   |   2 -
 read-cache.c      | 258 +++++++++++++++++++++++-----------------------
 unpack-trees.c    |   4 +-
 unpack-trees.h    |   3 -
 8 files changed, 139 insertions(+), 154 deletions(-)