remove #[cmse_nonsecure_entry]

compiler/rustc_error_codes/src/error_codes/E0775.md

@@ -3,11 +3,10 @@ extension.
 
 Erroneous code example:
 
-```compile_fail,E0775
+```ignore (no longer emitted)
 #![feature(cmse_nonsecure_entry)]
 
-#[cmse_nonsecure_entry]
-pub extern "C" fn entry_function() {}
+pub extern "C-cmse-nonsecure-entry" fn entry_function() {}
 ```
 
 To fix this error, compile your code for a Rust target that supports the

compiler/rustc_error_codes/src/error_codes/E0776.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 `#[cmse_nonsecure_entry]` functions require a C ABI
 
 Erroneous code example:
 
-```compile_fail,E0776
+```ignore (no longer emitted)
 #![feature(cmse_nonsecure_entry)]
 
 #[no_mangle]