[DOC] doc: improve navigation to main doc page

also, fixes a small error

README.md

@@ -87,7 +87,11 @@ find some more information [here](doc/comparison.md).
 
 ## Documentation
 
-The complete documentation can be found [here](doc/readme.md). The most important sections are:
+A complete documentation for Owl can be found here:
+
+- [Main documentation page](doc/readme.md).
+
+The most important sections are:
 
 - [Quick Start](doc/quick_start.md)
 - [Component](doc/component.md)

doc/event_bus.md

@@ -5,7 +5,7 @@ parts of the code. Owl has a very simple bus class, which manages subscriptions,
 triggering events, and callbacks.
 
 ```js
-const bus = new owl.EventBus();
+const bus = new owl.core.EventBus();
 
 bus.on("some-event", null, function(...args) {
   console.log(...args);