Add diagnostic items for a few of core's builtin macros

Author: thomcc

Diff for: library/core/src/macros/mod.rs

@@ -1044,6 +1044,7 @@ pub(crate) mod builtin {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_builtin_macro]
     #[macro_export]
+    #[rustc_diagnostic_item = "env_macro"] // useful for external lints
     macro_rules! env {
         ($name:expr $(,)?) => {{ /* compiler built-in */ }};
         ($name:expr, $error_msg:expr $(,)?) => {{ /* compiler built-in */ }};
@@ -1074,6 +1075,7 @@ pub(crate) mod builtin {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_builtin_macro]
     #[macro_export]
+    #[rustc_diagnostic_item = "option_env_macro"] // useful for external lints
     macro_rules! option_env {
         ($name:expr $(,)?) => {{ /* compiler built-in */ }};
     }
@@ -1479,6 +1481,7 @@ pub(crate) mod builtin {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_builtin_macro]
     #[macro_export]
+    #[rustc_diagnostic_item = "include_macro"] // useful for external lints
     macro_rules! include {
         ($file:expr $(,)?) => {{ /* compiler built-in */ }};
     }