Add "Features removed" section to CHANGES

CHANGES

@@ -9,6 +9,28 @@ Incompatible changes
 * LaTeX ``\includegraphics`` command isn't overloaded: only ``\sphinxincludegraphics``
   has the custom code to fit image to available width if oversized.
 
+Features removed
+----------------
+
+* Configuration variables
+
+  - epub3_contributor
+  - epub3_description
+  - epub3_page_progression_direction
+  - html_translator_class
+  - html_use_modindex
+  - latex_font_size
+  - latex_paper_size
+  - latex_preamble
+  - latex_use_modindex
+  - latex_use_parts
+
+* ``termsep`` node
+* defindex.html template
+* LDML format support in `today`, `today_fmt` and `html_last_updated_fmt`
+* ``:inline:`` option for the directives of sphinx.ext.graphviz extension
+* sphinx.ext.pngmath extension
+
 Features added
 --------------