Use pre-interned symbols in import recovery

compiler/rustc_span/src/symbol.rs

@@ -782,6 +782,7 @@ symbols! {
         impl_lint_pass,
         impl_macros,
         impl_trait_in_bindings,
+        import,
         import_shadowing,
         imported_main,
         in_band_lifetimes,
@@ -1519,6 +1520,7 @@ symbols! {
         use_nested_groups,
         used,
         used_with_arg,
+        using,
         usize,
         v1,
         va_arg,