Log Message:
devel/difftastic: update to 0.28.0

Parsing
-Added support for HCL, Perl and Swift.
-Improved language detection for JSON. More file extensions and file names are
 recognised as JSON, e.g. .jsonl.

Display
-Fixed crash in inline mode.
-Added an option --tab-width that controls how many spaces are used to display
 tabs. The default value is 8, consistent with older versions.
-Added an option --syntax-highlight that controls whether the output is syntax
 highlighted.

Diffing
-Difftastic now diffs files in parallel when diffing whole directories,
 increasing performance.
-Directory diffing now correctly handles files that are only in one of the
 directories.

Command Line Interface
-Fixed handling of paths that aren't valid UTF-8.
--missing-as-empty now only applies when diffing files, and has no effect when
 diffing directories.