bug#54034: 29.0.50; Diff prettify broken for empty files

[Matthias Meulien]

Matthias Meulien <orontee@gmail.com> writes:

> When `diff-font-lock-prettify' is non-nil, the fontification of a diff
> where an empty file is added to a Git project is broken:

For binary files, there's an analog problem: One would expect
`diff-font-lock-prettify' to hide the "diff --git", "index", etc. lines
and display a user friendly line.