Add seealso sections to multidict docs

Author: asvetlov

docs/multidict.rst

@@ -200,6 +200,11 @@ MutableMultiDict
       dictionary is then updated with those key/value pairs:
       ``d.update(red=1, blue=2)``.
 
+   .. seealso::
+
+      :class:`MultiDictProxy` can be used to create a read-only view
+      of a :class:`MultiDict`.
+
 
 CIMultiDict
 -----------
@@ -227,6 +232,11 @@ CIMultiDict
 
    The class is inherited from :class:`MultiDict`.
 
+   .. seealso::
+
+      :class:`CIMultiDictProxy` can be used to create a read-only view
+      of a :class:`CIMultiDict`.
+
 
 MultiDictProxy
 ---------------