Auto merge of rust-lang#131284 - dingxiangfei2009:rename-smart-ptr-to…

…-coerce-referent, r=compiler-errors

Rename macro `SmartPointer` to `CoercePointee`

As per resolution rust-lang#129104 we will rename the macro to better reflect the technical specification of the feature and clarify the communication.

- `SmartPointer` is renamed to `CoerceReferent`
- `#[pointee]` attribute is renamed to `#[referent]`
- `#![feature(derive_smart_pointer)]` gate is renamed to `#![feature(derive_coerce_referent)]`.
- Any mention of `SmartPointer` in the file names are renamed accordingly.

r? `@compiler-errors`

cc `@nikomatsakis` `@Darksonn`

core/src/marker.rs

@@ -1063,9 +1063,10 @@ pub trait FnPtr: Copy + Clone {
 }
 
 /// Derive macro generating impls of traits related to smart pointers.
-#[rustc_builtin_macro(SmartPointer, attributes(pointee))]
+#[rustc_builtin_macro(CoercePointee, attributes(pointee))]
 #[allow_internal_unstable(dispatch_from_dyn, coerce_unsized, unsize)]
-#[unstable(feature = "derive_smart_pointer", issue = "123430")]
-pub macro SmartPointer($item:item) {
+#[unstable(feature = "derive_coerce_pointee", issue = "123430")]
+#[cfg(not(bootstrap))]
+pub macro CoercePointee($item:item) {
     /* compiler built-in */
 }