Log Message:
mkvtoolnix: updated to 85.0

Version 85.0 "Shame For You" 2024-06-02

Bug fixes

* fixed compilation of `src/common/sorting.h` with certain compilers due to
  the deprecation & removal of `std::result_of<>` in C++20.
* fixed compilation with the `gtest` library when `gtest` requires additional
  libraries by querying `pkg-config` for the correct flags & libraries to
  build with.
* MKVToolNix GUI: multiplexer: restored the keyboard shortcut for switching to
  the "Attachments" tab (Alt+C for the English interface).
* MKVToolNix GUI: multiplexer: fixed several cases when the keyboard shortcuts
  for copying the first source file's name/the destination file's name to the
  title (Ctrl+F & Ctrl+D) and the one for copying the title to the destination
  file name (Ctrl+T) were not enabled.