Auto merge of #8286 - eefriedman:no-move, r=nox

Remove unnecessary uses of #[no_move]

The patch makes RootCollection a bit safer by making the StackRootTLS hold
it in place.

RootedVec was doing an extremely delicate dance and just hoping nobody
messed it up; switch to a Box to be safe.

CodeGenRust seemed to be using no_move for no particularly good reason.

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components/script/dom/bindings/mod.rs

@@ -152,9 +152,7 @@ pub mod xmlname;
 /// Generated JS-Rust bindings.
 #[allow(missing_docs, non_snake_case)]
 pub mod codegen {
-    // FIXME(#5853) we shouldn't need to
-    // allow moved_no_move here
-    #[allow(unrooted_must_root, moved_no_move)]
+    #[allow(unrooted_must_root)]
     pub mod Bindings {
         include!(concat!(env!("OUT_DIR"), "/Bindings/mod.rs"));
     }