Fix typos in E0224

Author: jumbatm

compiler/rustc_error_codes/src/error_codes/E0224.md

@@ -1,4 +1,4 @@
-A trait object was declaired with no traits.
+A trait object was declared with no traits.
 
 Erroneous code example:
 
@@ -8,7 +8,7 @@ type Foo = dyn 'static +;
 
 Rust does not currently support this.
 
-To solve ensure the the trait object has at least one trait:
+To solve, ensure that the trait object has at least one trait:
 
 ```
 type Foo = dyn 'static + Copy;