Refactor changes

Author: Polkaverse

src/librustc_error_codes/error_codes/E0703.md

@@ -8,9 +8,9 @@ extern "invalid" fn foo() {} // error!
 # fn main() {}
 ```
 
-At present there the few predefined ABI's (like Rust, C, system, etc.)
-which we can use in our Rust code. Please verify the ABI from the
-given ABI. For example you can replace the given ABI from 'Rust'.
+At present few predefined ABI's (like Rust, C, system, etc.) can be
+used in Rust. Verify that the ABI is predefined. For example you can
+replace the given ABI from 'Rust'.
 
 ```
 extern "Rust" fn foo() {} // ok!