doc fixes

Author: jll63

doc/headers_namespaces.adoc

@@ -2,9 +2,9 @@
 ## Headers and Namespaces
 
 Most real-life programs will be organized in multiple files and multiple
-namespaces. OpenMethod interacts with headers and namespaces very naturally,
-unless using-directives are avoided. In that case, there are a few things to be
-aware of.
+namespaces. OpenMethod interacts with headers and namespaces naturally, if
+using-directives are avoided. In that case, there are a few things to be aware
+of.
 
 Let's break the Animals example into headers and namespaces. First we put
 `Animal` in its own header and namespace:

doc/hello_world.adoc

@@ -96,8 +96,3 @@ reference, because `virtual_ptr` has a conversion constructor for that:
 ----
 include::{examplesdir}/hello_world.cpp[tag=call]
 ----
-
-NOTE: `virtual_ptr` is more like a reference than a pointer: it cannot be null,
-and it cannot be re-assigned. The only reason why it is not called `virtual_ref`
-is to save the name in case it becomes possible to overload the dot operator in
-future versions of C++.