rustc_lint: Remove unused_crate_dependencies from the unused group

src/librustc_lint/lib.rs

@@ -276,7 +276,6 @@ fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
         UNUSED_ALLOCATION,
         UNUSED_DOC_COMMENTS,
         UNUSED_EXTERN_CRATES,
-        UNUSED_CRATE_DEPENDENCIES,
         UNUSED_FEATURES,
         UNUSED_LABELS,
         UNUSED_PARENS,

src/test/ui/unused-crate-deps/lint-group.rs

@@ -0,0 +1,9 @@
+// `unused_crate_dependencies` is not currently in the `unused` group
+// due to false positives from Cargo.
+
+// check-pass
+// aux-crate:bar=bar.rs
+
+#![deny(unused)]
+
+fn main() {}