Remove unknown lint from deny attribute

src/librustc_error_codes/error_codes/E0710.md

@@ -16,15 +16,6 @@ fn main() {
 }
 ```
 
-```compile_fail,E0710
-fn main() {
-    #![deny(clipp::filter_map)] //error!
-    fn filter() {
-        //logic
-    }
-}
-```
-
 Please verify you didn't misspell the tool's name or that you didn't
 forget to import it in you project:
 
@@ -41,12 +32,3 @@ fn main() {
     // business logic
 }
 ```
-
-```
-fn main() {
-    #![deny(clippy::filter_map)] // ok!
-    fn filter() {
-        //logic
-    }
-}
-```