Remove the code related to minimal_syntaxes.bin

To get fast startup, syntect will instead start to lazy-load syntaxes. See
https://github.com/trishume/syntect/pull/393 and discussions in linked PRs.

src/bin/bat/assets.rs

@@ -21,7 +21,6 @@ pub fn cache_dir() -> Cow<'static, str> {
 pub fn clear_assets() {
     clear_asset("themes.bin", "theme set cache");
     clear_asset("syntaxes.bin", "syntax set cache");
-    clear_asset("minimal_syntaxes.bin", "minimal syntax sets cache");
     clear_asset("metadata.yaml", "metadata file");
 }