Improve "Why this is bad" section

Co-authored-by: Ruby Lazuli <[email protected]>

Author: Sour1emon

clippy_lints/src/manual_is_power_of_two.rs

@@ -13,7 +13,7 @@ declare_clippy_lint! {
     /// Checks for expressions like `x.count_ones() == 1` or `x & (x - 1) == 0` which are manual
     /// reimplementations of `x.is_power_of_two()``
     /// ### Why is this bad?
-    /// It's simpler and clearer
+    /// Manual reimplementations of `is_power_of_two` increase code complexity for little benefit.
     /// ### Example
     /// ```no_run
     /// let x: u32 = 1;