prev 1.4.0

Added

• Keyboard shortcuts can be changed in the [keys] table of the
  settings file, for every system or for one; menus on macOS and the
  hints prev shows name the shortcuts in effect.
• A Make Default button in Settings makes prev the system's default app
  for the file types it opens, with a dot showing whether none, some or
  all of them open with prev. On macOS it asks for the common types,
  which macOS confirms one by one; on Windows it opens prev's page in
  Default apps.

Changed

• A selected annotation shows a thin blue box with square handles,
  the same in every theme.
• On Windows, HEIC and AVIF come from one smaller heif.dll.
• On macOS, HEIC and AVIF open without Homebrew: prev.app carries a
  decode-only libheif.
• The tour of prev shows each system's differences and has an
  Inspector section, and page reordering is shown as an animation.