docs(aio): fix TS warning error - filter expects a boolean function param (#22954)

PR Close #22954

aio/content/examples/rx-library/src/operators.2.ts

@@ -8,7 +8,7 @@ import { map } from 'rxjs/operators/map';
 
 const squareOdd = Observable.of(1, 2, 3, 4, 5)
   .pipe(
-    filter(n => n % 2),
+    filter(n => n % 2 !== 0),
     map(n => n * n)
   );