Add a couple clarifications

pep-0428.txt

@@ -291,6 +291,14 @@ Extraneous path separators and ``"."`` components are eliminated, but not
     >>> PurePosixPath('a/../b')
     PurePosixPath('a/../b')
 
+Multiple leading slashes are treated differently depending on the path
+flavour::
+
+    >>> PurePosixPath('//some/path')
+    PurePosixPath('/some/path')
+    >>> PureNTPath('//some/path')
+    PureNTPath('\\\\some\\path\\')
+
 Calling the constructor without any argument creates a path object pointing
 to the logical "current directory"::
 
@@ -309,10 +317,13 @@ A path can be joined with another using the ``__getitem__`` operator::
     >>> p[PurePosixPath('bar')]
     PurePosixPath('foo/bar')
 
-As with constructing, multiple path components can be specified at once::
+As with constructing, multiple path components can be specified, either
+collapsed or separately::
 
     >>> p['bar/xyzzy']
     PurePosixPath('foo/bar/xyzzy')
+    >>> p['bar', 'xyzzy']
+    PurePosixPath('foo/bar/xyzzy')
 
 A join() method is also provided, with the same behaviour.  It can serve
 as a factory function::