refactor: Avoid unnecessary uses of enumerate().

src/util/argstr.rs

@@ -76,15 +76,7 @@ impl<'a> ArgStr<'a> {
     pub(crate) fn trim_start_n_matches(&self, n: usize, ch: u8) -> ArgStr {
         assert!(ch.is_ascii());
 
-        let i = self
-            .0
-            .iter()
-            .take(n)
-            .take_while(|c| **c == ch)
-            .enumerate()
-            .last()
-            .map(|(i, _)| i + 1)
-            .unwrap_or(0);
+        let i = self.0.iter().take(n).take_while(|c| **c == ch).count();
 
         self.split_at_unchecked(i).1
     }

src/util/graph.rs

@@ -30,12 +30,7 @@ where
             self.0.push(Child::new(req));
             idx
         } else {
-            self.0
-                .iter()
-                .enumerate()
-                .find(|(_, e)| e.id == req)
-                .map(|(i, _)| i)
-                .unwrap()
+            self.0.iter().position(|e| e.id == req).unwrap()
         }
     }