make never_loop applicability more flexible

tests/ui/never_loop_fixable.fixed

@@ -0,0 +1,20 @@
+#![allow(clippy::iter_next_slice, clippy::needless_return)]
+
+fn no_break_or_continue_loop() {
+    if let Some(i) = [1, 2, 3].iter().next() {
+        //~^ never_loop
+        return;
+    }
+}
+
+fn no_break_or_continue_loop_outer() {
+    if let Some(i) = [1, 2, 3].iter().next() {
+        //~^ never_loop
+        return;
+        loop {
+            if true {
+                continue;
+            }
+        }
+    }
+}