Issue #3382. float 'F' formatting no longer maps to 'f'. This only affects nan and inf.
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index d104931..959ea99 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -415,7 +415,8 @@
| ``'f'`` | Fixed point. Displays the number as a fixed-point |
| | number. |
+---------+----------------------------------------------------------+
- | ``'F'`` | Fixed point. Same as ``'f'``. |
+ | ``'F'`` | Fixed point. Same as ``'f'``, but converts ``nan`` to |
+ | | ``NAN`` and ``inf`` to ``INF``. |
+---------+----------------------------------------------------------+
| ``'g'`` | General format. This prints the number as a fixed-point |
| | number, unless the number is too large, in which case |