Auto merge of #74246 - GuillaumeGomez:cleanup-e0719, r=Dylan-DPC

Clean up E0719 explanation

r? @Dylan-DPC

Author: bors

src/librustc_error_codes/error_codes/E0719.md

@@ -1,4 +1,4 @@
-The value for an associated type has already been specified.
+An associated type value was specified more than once.
 
 Erroneous code example:
 
@@ -25,7 +25,7 @@ trait FooTrait {}
 trait BarTrait {}
 trait FooBarTrait: FooTrait + BarTrait {}
 
-struct Foo<T: Iterator<Item: FooBarTrait>> { f: T }
+struct Foo<T: Iterator<Item: FooBarTrait>> { f: T } // ok!
 ```
 
 For more information about associated types, see [the book][bk-at]. For more