Doc codeblock fixup

clippy_lints/src/fn_null_check.rs

@@ -21,7 +21,7 @@ declare_clippy_lint! {
     /// if (fn_ptr as *const ()).is_null() { ... }
     /// ```
     /// Use instead:
-    /// ```rust
+    /// ```rust,ignore
     /// let fn_ptr: Option<fn()> = /* somehow obtained nullable function pointer */
     ///
     /// if fn_ptr.is_none() { ... }

clippy_lints/src/transmute/mod.rs

@@ -426,7 +426,7 @@ declare_clippy_lint! {
     ///
     /// ### Example
     /// ```rust
-    /// let null_fn: fn() = unsafe { std::mem::transmute( std::ptr::null() ) };
+    /// let null_fn: fn() = unsafe { std::mem::transmute( std::ptr::null::<()>() ) };
     /// ```
     /// Use instead:
     /// ```rust