fix: if previously not found, still look up icon

This fixes the case where an icon was previously looked up, not found, and now exists (i.e. when an application was installed)

src/lib.rs

@@ -227,10 +227,7 @@ impl<'a> LookupBuilder<'a> {
                 CacheEntry::Found(icon) => {
                     return Some(icon);
                 }
-                CacheEntry::NotFound => {
-                    return None;
-                }
-                CacheEntry::Unknown => {}
+                _ => {}
             };
         }