rustdoc: remove rust logo from non-Rust crates

compiler/rustc_parse_format/src/lib.rs

@@ -9,6 +9,9 @@
     html_playground_url = "https://play.rust-lang.org/",
     test(attr(deny(warnings)))
 )]
+#![cfg_attr(not(bootstrap), doc(rust_logo))]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
+#![cfg_attr(not(bootstrap), feature(rustdoc_internals))]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 // We want to be able to build this crate with a stable compiler, so no