Log Message:
devel/difftastic: update to 0.40.0

0.40 (released 28th December 2022)

Diffing
 - Diffing is now more efficient: the generated graphs have ~20% fewer vertices.
   This improves performance (less memory, shorter runtime), and also enables
   difftastic to handle larger files (you're less likely to reach
   DFT_GRAPH_LIMIT). This improvement was contributed by @QuarticCat, thanks!

Parsing
 - rebar files (e.g. rebar.lock) are no longer associated with Erlang, only
   *.erl files, as the Erlang parser does not currently support them.

Command Line Interface
 --list-languages now shows filenames associated with languages (e.g.
 Cargo.lock is TOML) in addition to extensions.

Display
 - Symlinks are now expanded before calculating relative paths, resulting in
   relative paths being shown in more cases.