fix clippy::option_if_let_else

Author: hellow554

src/adaptors/multi_product.rs

@@ -114,11 +114,7 @@ impl<I> MultiProduct<I>
     /// Returns true if iteration has started and has not yet finished; false
     /// otherwise.
     fn in_progress(&self) -> bool {
-        if let Some(last) = self.0.last() {
-            last.in_progress()
-        } else {
-            false
-        }
+        self.0.last().map_or(false, |last| last.in_progress())
     }
 }