Add a better comment explaining why onFocus is empty

src/AztecView.js

@@ -139,7 +139,10 @@ class AztecView extends React.Component {
           onHTMLContentWithCursor = { this._onHTMLContentWithCursor }
           onSelectionChange = { this._onSelectionChange }
           onEnter = { this._onEnter }
-          onFocus = { () => {} } // Do nothing here, the onPress takes care of everything
+          // IMPORTANT: the onFocus events are thrown away as these are handled by onPress() in the upper level.
+          // It's necessary to do this otherwise onFocus may be set by `{...otherProps}` and thus the onPress + onFocus
+          // combination generate an infinite loop as described in https://github.com/wordpress-mobile/gutenberg-mobile/issues/302
+          onFocus = { () => {} } 
           onBlur = { this._onBlur }
           onBackspace = { this._onBackspace }
         />