Maud is not building on the latest nightly

[barzamin]

error[E0614]: type `syntax::symbol::InternedString` cannot be dereferenced
  --> maud_lints/src/util.rs:33:87
   |
33 |     apb.names.len() == path.len() && apb.names.iter().zip(path.iter()).all(|(a, &b)| &**a == b)
   |                                                                                       ^^^
error[E0308]: mismatched types
  --> maud_lints/src/util.rs:27:29
   |
27 |             self.names.push(Symbol::intern(text).as_str());
   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected struct `syntax::symbol::InternedString`, found struct `syntax::symbol::LocalInternedString`
   |
   = note: expected type `syntax::symbol::InternedString`
              found type `syntax::symbol::LocalInternedString`
error: aborting due to 2 previous errors

Due to rust-lang/rust#49894.