update links to make_ascii_lowercase for slice to point to methods on the same type, rather than on u8

Author: geeklint

library/alloc/src/slice.rs

@@ -642,7 +642,7 @@ impl [u8] {
     ///
     /// To uppercase the value in-place, use [`make_ascii_uppercase`].
     ///
-    /// [`make_ascii_uppercase`]: u8::make_ascii_uppercase
+    /// [`make_ascii_uppercase`]: #method.make_ascii_uppercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[inline]
     pub fn to_ascii_uppercase(&self) -> Vec<u8> {
@@ -659,7 +659,7 @@ impl [u8] {
     ///
     /// To lowercase the value in-place, use [`make_ascii_lowercase`].
     ///
-    /// [`make_ascii_lowercase`]: u8::make_ascii_lowercase
+    /// [`make_ascii_lowercase`]: #method.make_ascii_lowercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[inline]
     pub fn to_ascii_lowercase(&self) -> Vec<u8> {