Instead of adding a paragraph mentioning std::mem::transmute and core::mem::transmute, create documentation pages for them.

This renders them discoverable via search. I removed the mention of the exports in the transmute documentation, but can re-add it if desired.

src/libcore/intrinsics.rs

@@ -729,10 +729,6 @@ extern "rust-intrinsic" {
     /// cause [undefined behavior][ub] with this function. `transmute` should be
     /// the absolute last resort.
     ///
-    /// `transmute` is re-exported by [core::mem](../mem/index.html) as
-    /// `core::mem::transmute`, which may be used without the `core_intrinsics`
-    /// feature flag.
-    ///
     /// The [nomicon](../../nomicon/transmutes.html) has additional
     /// documentation.
     ///

src/libcore/mem.rs

@@ -15,6 +15,7 @@ use ptr;
 use ops::{Deref, DerefMut};
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(inline)]
 pub use intrinsics::transmute;
 
 /// Takes ownership and "forgets" about the value **without running its destructor**.