Remove BooleanType from docs/StdlibRationales.rst

Author: benrimmington

docs/StdlibRationales.rst

@@ -174,21 +174,6 @@ call an API with a different name, say ``lazyEnumerate()`` to opt into
 laziness.  The problem is that the eager API, which would have a shorter and
 less obscure name, would be less efficient for the common case.
 
-Use of ``BooleanType`` in library APIs
---------------------------------------
-
-Use ``Bool`` instead of a generic function over a ``BooleanType``, unless there
-are special circumstances (for example, ``func &&`` is designed to work on all
-boolean values so that ``&&`` feels like a part of the language).
-
-``BooleanType`` is a protocol to which only ``Bool`` and ``ObjCBool`` conform.
-Users don't usually interact ``ObjCBool`` instances, except when using certain
-specific APIs (for example, APIs that operate on pointers to ``BOOL``).  If
-someone already has an ``ObjCBool`` instance for whatever strange reason, they
-can just convert it to ``Bool``.  We think this is the right tradeoff:
-simplifying function signatures is more important than making a marginal
-usecase a bit more convenient.
-
 Possible future directions
 ==========================