Unhide HINT_HIDDEN from slices api and rename to HINT_SHORTCUT

Test: manual, build a slice with HINT_SHORTCUT, note content doesn't appear
      in slice template but can appear when displayed as shortcut
Bug: 68378574
Change-Id: I4f7d0b8dbbcb0da4efe79a709b0d9fbf24026a6e
2 files changed