PYTHON-942 - Fix changelog guidance to no_cursor_timeout.

Author: behackett

doc/changelog.rst

@@ -379,7 +379,6 @@ changes are not significant for your application.
 
 - spec -> filter
 - fields -> projection
-- timeout -> no_cursor_timeout
 - partial -> allow_partial_results
 
 The following find/find_one options have been added:
@@ -415,6 +414,13 @@ The following find/find_one options are deprecated:
 
 - manipulate
 
+The following renames need special handling.
+
+- timeout -> no_cursor_timeout -
+ The default for `timeout` was True. The default for `no_cursor_timeout` is
+ False. If you were previously passing False for `timeout` you must pass
+ **True** for `no_cursor_timeout` to keep the previous behavior.
+
 :mod:`~pymongo.errors` changes
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