Auto merge of #85910 - cjgillot:no-meta-version, r=Aaron1011

Drop metadata_encoding_version.

Part of #85153

r? `@Aaron1011`

compiler/rustc_metadata/src/lib.rs

@@ -29,3 +29,5 @@ mod rmeta;
 pub mod creader;
 pub mod dynamic_lib;
 pub mod locator;
+
+pub use rmeta::METADATA_HEADER;