rename rustc_attr to rustc_attr_parsing and create rustc_attr_data_structures

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -0,0 +1,17 @@
+mod allow_unstable;
+mod cfg;
+mod confusables;
+mod deprecation;
+mod repr;
+mod stability;
+mod transparency;
+
+pub mod util;
+
+pub use allow_unstable::*;
+pub use cfg::*;
+pub use confusables::*;
+pub use deprecation::*;
+pub use repr::*;
+pub use stability::*;
+pub use transparency::*;