fn is_align_to: move some comments closer to the cast they refer to

Author: RalfJung

library/core/src/ptr/const_ptr.rs

@@ -1628,12 +1628,12 @@ impl<T: ?Sized> *const T {
         #[inline]
         const fn const_impl(ptr: *const (), align: usize) -> bool {
             // We can't use the address of `self` in a `const fn`, so we use `align_offset` instead.
-            // The cast to `()` is used to
-            //   1. deal with fat pointers; and
-            //   2. ensure that `align_offset` doesn't actually try to compute an offset.
             ptr.align_offset(align) == 0
         }
 
+        // The cast to `()` is used to
+        //   1. deal with fat pointers; and
+        //   2. ensure that `align_offset` (in `const_impl`) doesn't actually try to compute an offset.
         #[cfg_attr(not(bootstrap), allow(unused_unsafe))] // on bootstrap bump, remove unsafe block
         // SAFETY: The two versions are equivalent at runtime.
         unsafe {

library/core/src/ptr/mut_ptr.rs

@@ -1900,12 +1900,12 @@ impl<T: ?Sized> *mut T {
         #[inline]
         const fn const_impl(ptr: *mut (), align: usize) -> bool {
             // We can't use the address of `self` in a `const fn`, so we use `align_offset` instead.
-            // The cast to `()` is used to
-            //   1. deal with fat pointers; and
-            //   2. ensure that `align_offset` doesn't actually try to compute an offset.
             ptr.align_offset(align) == 0
         }
 
+        // The cast to `()` is used to
+        //   1. deal with fat pointers; and
+        //   2. ensure that `align_offset` (in `const_impl`) doesn't actually try to compute an offset.
         #[cfg_attr(not(bootstrap), allow(unused_unsafe))] // on bootstrap bump, remove unsafe block
         // SAFETY: The two versions are equivalent at runtime.
         unsafe {