Add Documentation within Editor

Sample code:

```
Documentation
DocumentationIndexer[qml]

DocumentationUrl durl = DocumentationIndexer[qml].find("opencv.contrib.core", "TLDTracker", "speed")
durl.type == "html" => return QmlComponent("html").load(durl)
durl.type == "md" => return QmlComponent("md").load(durl)
```