Auto merge of #15403 - servo:warnings, r=SimonSapin

Remove a gate for the stabilized more_struct_aliases feature.

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components/script/lib.rs

@@ -7,7 +7,6 @@
 #![feature(const_fn)]
 #![feature(core_intrinsics)]
 #![feature(field_init_shorthand)]
-#![feature(more_struct_aliases)]
 #![feature(mpsc_select)]
 #![feature(nonzero)]
 #![feature(on_unimplemented)]