Auto merge of #104481 - matthiaskrgr:rollup-hf8rev0, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #103484 (Add `rust` to `let_underscore_lock` example)
 - #103489 (Make `pointer::byte_offset_from` more generic)
 - #104193 (Shift no characters when using raw string literals)
 - #104348 (Respect visibility & stability of inherent associated types)
 - #104401 (avoid memory leak in mpsc test)
 - #104419 (Fix test/ui/issues/issue-30490.rs)
 - #104424 (rustdoc: remove no-op CSS `.popover { font-size: 1rem }`)
 - #104425 (rustdoc: remove no-op CSS `.main-header { justify-content }`)
 - #104450 (Fuchsia test suite script fix)
 - #104471 (Update PROBLEMATIC_CONSTS in style.rs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

core/src/ptr/const_ptr.rs

@@ -709,7 +709,7 @@ impl<T: ?Sized> *const T {
     #[unstable(feature = "pointer_byte_offsets", issue = "96283")]
     #[rustc_const_unstable(feature = "const_pointer_byte_offsets", issue = "96283")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
-    pub const unsafe fn byte_offset_from(self, origin: *const T) -> isize {
+    pub const unsafe fn byte_offset_from<U: ?Sized>(self, origin: *const U) -> isize {
         // SAFETY: the caller must uphold the safety contract for `offset_from`.
         unsafe { self.cast::<u8>().offset_from(origin.cast::<u8>()) }
     }

core/src/ptr/mut_ptr.rs

@@ -889,7 +889,7 @@ impl<T: ?Sized> *mut T {
     #[unstable(feature = "pointer_byte_offsets", issue = "96283")]
     #[rustc_const_unstable(feature = "const_pointer_byte_offsets", issue = "96283")]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
-    pub const unsafe fn byte_offset_from(self, origin: *const T) -> isize {
+    pub const unsafe fn byte_offset_from<U: ?Sized>(self, origin: *const U) -> isize {
         // SAFETY: the caller must uphold the safety contract for `offset_from`.
         unsafe { self.cast::<u8>().offset_from(origin.cast::<u8>()) }
     }

std/src/sync/mpsc/tests.rs

@@ -713,10 +713,11 @@ fn issue_39364() {
     let t = thread::spawn(move || {
         thread::sleep(Duration::from_millis(300));
         let _ = tx.clone();
-        crate::mem::forget(tx);
+        // Don't drop; hand back to caller.
+        tx
     });
 
     let _ = rx.recv_timeout(Duration::from_millis(500));
-    t.join().unwrap();
+    let _tx = t.join().unwrap(); // delay dropping until end of test
     let _ = rx.recv_timeout(Duration::from_millis(500));
 }