convert the optimize attribute to a new parser

compiler/rustc_error_codes/src/error_codes/E0722.md

@@ -1,8 +1,14 @@
+#### Note: this error code is no longer emitted by the compiler
+
+This is because it was too specific to the `optimize` attribute.
+Similar diagnostics occur for other attributes too.
+The example here will now emit `E0539`
+
 The `optimize` attribute was malformed.
 
 Erroneous code example:
 
-```compile_fail,E0722
+```compile_fail,E0539
 #![feature(optimize_attribute)]
 
 #[optimize(something)] // error: invalid argument

compiler/rustc_error_codes/src/lib.rs

@@ -686,6 +686,7 @@ E0805: 0805,
 //  E0707, // multiple elided lifetimes used in arguments of `async fn`
 //  E0709, // multiple different lifetimes used in arguments of `async fn`
 //  E0721, // `await` keyword
+//  E0722, // replaced with a generic attribute input check
 //  E0723, // unstable feature in `const` context
 //  E0738, // Removed; errored on `#[track_caller] fn`s in `extern "Rust" { ... }`.
 //  E0744, // merged into E0728