servo: Merge #10152 - Fix #9511. Export webidl enums using "pub use" …

…(from jdm:9511-rebase); r=nox

Change typedef codegen to export the underlying enum itself, rather
than an alias. Works around rust-lang/rust#31355

Rebase of #9691.

Source-Repo: https://github.com/servo/servo
Source-Revision: edcf24fd4d39e86548717ecdfe36e2f1df30daac

UltraBlame original commit: 00562e792f94bec284362eb890efac88f6ce30c2

servo/components/script/dom/bindings/codegen/CodegenRust.py

@@ -40425,10 +40425,22 @@
 "
 \
 npub
-type
+use
+dom
+:
+:
+bindings
+:
+:
+codegen
+:
+:
+UnionTypes
+:
+:
 %
 s
-=
+as
 %
 s
 ;
@@ -40438,25 +40450,16 @@
 n
 "
 %
+                                           
 (
 t
 .
+innerType
+t
+.
 identifier
 .
 name
-                                                                        
-"
-UnionTypes
-:
-:
-"
-+
-str
-(
-t
-.
-innerType
-)
 )
 )
 ]