Update changelog.

CHANGES.rst

@@ -2,7 +2,7 @@
 Cython Changelog
 ================
 
-0.28 (2018-??-??)
+0.28 (2018-03-??)
 =================
 
 Features added
@@ -18,6 +18,10 @@ Features added
 * The ``const`` modifier can be applied to memoryview declarations to allow
   read-only buffers as input.  (Github issues #1605, #1869)
 
+* C code in the docstring of a ``cdef extern`` block is copied verbatimly
+  into the generated file.
+  Patch by Jeroen Demeyer.  (Github issue #1915)
+
 * When compiling with gcc, the module init function is now tuned for small
   code size instead of whatever compile flags were provided externally.
   Cython now also disables some code intensive optimisations in that function
@@ -84,6 +88,9 @@ Features added
 * Some missing signals were added to ``libc/signal.pxd``.
   Patch by Jeroen Demeyer.  (Github issue #1914)
 
+* The warning about repeated extern declarations is now visible by default.
+  (Github issue #1874)
+
 * The exception handling of the function types used by CPython's type slot
   functions was corrected to match the de-facto standard behaviour, so that
   code that uses them directly benefits from automatic and correct exception
@@ -146,9 +153,6 @@ Bugs fixed
 * The builtin ``bytearray`` type could not be used as base type of cdef classes.
   (Github issue #2106)
 
-* Overloaded C++ functions no longer issue warnings about redeclarations.
-  (Github issue #2013)
-
 Other changes
 -------------