stop running code samples in the error code .md

Author: folkertdev

compiler/rustc_error_codes/src/error_codes/E0798.md

@@ -11,7 +11,7 @@ see [arm's aapcs32](https://github.com/ARM-software/abi-aa/releases).
 
 Erroneous code example:
 
-```compile_fail,E0798
+```ignore (only fails on supported targets)
 #![feature(abi_c_cmse_nonsecure_call)]
 
 #[no_mangle]
@@ -26,7 +26,7 @@ Arguments' alignment is respected. In the example below, padding is inserted
 so that the `u64` argument is passed in registers r2 and r3. There is then no
 room left for the final `f32` argument
 
-```compile_fail,E0798
+```ignore (only fails on supported targets)
 #![feature(abi_c_cmse_nonsecure_call)]
 
 #[no_mangle]