Rollup merge of rust-lang#76117 - mark-i-m:patch-1, r=petrochenkov

Update README.md

Author: matklad

src/README.md

@@ -1,5 +1,5 @@
 This directory contains the source code of the rust project, including:
-- `rustc` and its tests
+- The test suite
 - The bootstrapping build system
 - Various submodules for tools, like rustdoc, rls, etc.