Auto merge of #31631 - jonas-schievink:agoraphobia, r=nrc

[breaking-batch] Move more uses of `panictry!` out of libsyntax

src/librustdoc/lib.rs

@@ -43,7 +43,7 @@ extern crate rustc_back;
 extern crate rustc_front;
 extern crate rustc_metadata;
 extern crate serialize;
-extern crate syntax;
+#[macro_use] extern crate syntax;
 extern crate test as testing;
 extern crate rustc_unicode;
 #[macro_use] extern crate log;