Fix docs for suspicious_xor_used_as_pow lint

There was a tab after the three leading slashes which caused the
contents of the "Why is this bad?" section to be rendered as a code
block.

clippy_lints/src/suspicious_xor_used_as_pow.rs

@@ -9,7 +9,7 @@ declare_clippy_lint! {
     /// ### What it does
     /// Warns for a Bitwise XOR (`^`) operator being probably confused as a powering. It will not trigger if any of the numbers are not in decimal.
     /// ### Why is this bad?
-    ///	It's most probably a typo and may lead to unexpected behaviours.
+    /// It's most probably a typo and may lead to unexpected behaviours.
     /// ### Example
     /// ```rust
     /// let x = 3_i32 ^ 4_i32;