Removed ChronicleHash.context() method and changed acquireContext() return type from deprecated MapKeyContext to Closeable

src/main/java/net/openhft/chronicle/set/SetFromMap.java

@@ -123,11 +123,6 @@ class SetFromMap<E> extends AbstractSet<E>
         return m.longSize();
     }
 
-    @Override
-    public KeyContext context(E key) {
-        return m.context(key);
-    }
-
     @Override
     public Class<E> keyClass() {
         return m.keyClass();