rustdoc: remove rust logo from non-Rust crates

library/proc_macro/src/lib.rs

@@ -17,6 +17,8 @@
     test(no_crate_inject, attr(deny(warnings))),
     test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
 )]
+#![cfg_attr(not(bootstrap), doc(rust_logo))]
+#![cfg_attr(not(bootstrap), feature(rustdoc_internals))]
 // This library is copied into rust-analyzer to allow loading rustc compiled proc macros.
 // Please avoid unstable features where possible to minimize the amount of changes necessary
 // to make it compile with rust-analyzer on stable.