Function write_filtered_diff

pub(crate) fn write_filtered_diff<Filter>(
    diff_filename: &str,
    out_dir: &Path,
    compare_dir: &Path,
    verbose: bool,
    filter: Filter,
) -> bool
where
    Filter: Fn(FileType, Option<&str>) -> bool,

Filters based on filetype and extension whether to diff a file.

Returns whether any data was actually written.