Change naive_bytecount applicability MaybeIncorrect

We can't use `MachineApplicable` here as applying the fix will cause
another error because `bytecount` would first have to be added to the
Cargo.toml.

clippy_lints/src/bytecount.rs

@@ -86,7 +86,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ByteCount {
                         } else {
                             &filter_args[0]
                         };
-                        let mut applicability = Applicability::MachineApplicable;
+                        let mut applicability = Applicability::MaybeIncorrect;
                         span_lint_and_sugg(
                             cx,
                             NAIVE_BYTECOUNT,