improve doc comment

Co-authored-by: Philipp Oppermann <dev@phil-opp.com>

src/registers/control.rs

@@ -256,7 +256,7 @@ mod x86_64 {
             VirtAddr::new(Self::read_raw())
         }
 
-        /// Read the current page fault linear address from the CR2 register.
+        /// Read the current page fault linear address from the CR2 register as a raw `u64`.
         #[inline]
         pub fn read_raw() -> u64 {
             let value: u64;