l10n: po-id for 2.43 (round 1)

Update following components:

  * builtin/gc.c
  * builtin/interpret-trailers.c
  * builtin/merge-file.c
  * builtin/show-ref.c
  * builtin/update-index.c
  * chunk-format.c
  * parse-options.c
  * scalar.c

While at it, drop unused strings.

Signed-off-by: Bagas Sanjaya <[email protected]>