Clarify behavior of yield from in async generators

Author: ZeroIntensity

peps/pep-0828.rst

@@ -374,8 +374,9 @@ Using ``yield from`` to delegate to asynchronous generators
 
 It has been argued that many developers may intuitively believe that using a
 plain ``yield from`` inside an asynchronous generator would also delegate to
-an asynchronous subgenerator rather than a synchronous subgenerator, so it was
-proposed to make ``yield from`` always delegate to an asynchronous subgenerator.
+an asynchronous subgenerator rather than a synchronous subgenerator. As such,
+it was proposed to make ``yield from`` always delegate to an asynchronous
+subgenerator.
 
 For example:
 
@@ -397,7 +398,7 @@ synchronous constructs always have an asynchronous counterpart for use in
 asynchronous functions, instead of implicitly switching protocols depending on
 the type of function it is used in. For example, :keyword:`with` always means that the
 :term:`synchronous context management protocol <context management protocol>` will
-be invoked.
+be invoked, even when used in an ``async def`` function.
 
 Finally, this would leave a gap in asynchronous generators, because there would be
 no mechanism for delegating to a synchronous subgenerator. Even if this is not a