Fix typos (#6223)

- Add space on README.md page

README.md

@@ -116,7 +116,7 @@ The preparation of dataflows by applying various intermediate operators happens
 
 ```java
 Flowable<Integer> flow = Flowable.range(1, 5)
-.map(v -> v* v)
+.map(v -> v * v)
 .filter(v -> v % 3 == 0)
 ;
 ```