fix: Update CONTRIBUTING.md recommend -> recommended

Author: WhistlingZephyr

CONTRIBUTING.md

@@ -15,7 +15,7 @@ standard library in the [Standard library developers Guide][std-dev-guide], comm
 ## About the [rustc-dev-guide]
 
 The [rustc-dev-guide] is meant to help document how rustc –the Rust compiler– works,
-as well as to help new contributors get involved in rustc development. It is recommend
+as well as to help new contributors get involved in rustc development. It is recommended
 to read and understand the [rustc-dev-guide] before making a contribution. This guide
 talks about the different bots in the Rust ecosystem, the Rust development tools,
 bootstrapping, the compiler architecture, source code representation, and more.