Log Message:
devel/difftastic: update to 0.46.0

Command Line Interface
 - Removed the option --missing-as-empty. This is no longer needed as difftastic
   handles /dev/null gracefully on all platforms.

Parsing
 - Added support for Ada.
 - .ino files are now treated as C++.
 - Improved parsing for TOML.
 - Updated grammars for Bash, C, C++, C#, Clojure, CMake, Elixir, Go, Java,
   JavaScript, OCaml, Perl, QML and TypeScript.
 - Difftastic now prefers treating files as 'mostly UTF-8' or binary rather
   than UTF-16. Many files can be decoded as UTF-16 without decoding errors but
   produce nonsense results, so this heuristic seems to work better.
 - Fixed an issue where difftastic would discard the last newline in a file
   before diffing. This was most noticeable when doing textual diffs and the
   last line had changed.

Display
 - Difftastic no longer uses purple to highlight regions that are missing
   styling. This was intended as a debug feature, but it in practice it only
   highlighted trailing whitespace for a few languages.