Improve wording for PRO_DEF_WEAK_DISPATCH (#204)

Author: mingxwa

docs/PRO_DEF_WEAK_DISPATCH.md

@@ -4,7 +4,7 @@
 #define PRO_DEF_WEAK_DISPATCH // see below
 ```
 
-Macro `PRO_DEF_WEAK_DISPATCH` defines a "weak" dispatch type with a default implementation. It supports the following syntax:
+Macro `PRO_DEF_WEAK_DISPATCH` defines a "weak dispatch" type with a default implementation. It supports the following syntax:
 
 ```cpp
 PRO_DEF_WEAK_DISPATCH(dispatch_name, existing_dispatch, default_func_name);
@@ -26,7 +26,9 @@ struct dispatch_name : existing_dispatch {
 
 ## Notes
 
-A weak dispatch can extend an existing dispatch with a default implementation. This is useful when instantiating a `proxy<F>` with a value that does not support some conventions defined by `F`. Similar with [`PRO_DEF_FREE_DISPATCH`](PRO_DEF_FREE_DISPATCH.md), `default_func_name` can be the name of an arbitrary function or anything that supports `()` syntax, including a constructor.
+A "weak dispatch" can extend an existing dispatch with a default implementation that does not depend on the contained value of a `proxy` object. This is useful when instantiating a `proxy<F>` with a value that does not support some conventions defined by `F`. Similar to [`PRO_DEF_FREE_DISPATCH`](PRO_DEF_FREE_DISPATCH.md), `default_func_name` can be the name of an arbitrary function or anything that supports `()` syntax, including a constructor. Compared to wrapping the default implementation with [`PRO_DEF_FREE_DISPATCH`](PRO_DEF_FREE_DISPATCH.md), using "weak dispatch" when applicable can effectively improve compilation speed and binary size, in case some contained value of a `proxy` object does not participate code generation.
+
+In [Java](https://docs.oracle.com/javase/specs/jls/se23/html/jls-9.html#jls-9.4-200) or [C#](https://learn.microsoft.com/dotnet/csharp/language-reference/proposals/csharp-8.0/default-interface-methods), a "default method" can invoke other abstract methods defined in a same `interface`. This pattern is discouraged when using the "Proxy" library because the invocations are not necessarily indirect. If a "default implementation" otherwise needs to observe the contained value of a `proxy` object, it is encouraged to define a separate free function, and subsequently define a dispatch type of it by using [`PRO_DEF_FREE_DISPATCH`](PRO_DEF_FREE_DISPATCH.md) or [`PRO_DEF_FREE_AS_MEM_DISPATCH`](PRO_DEF_FREE_AS_MEM_DISPATCH.md).
 
 ## Example