address review: move impl-detail note

Author: skirpichev

Doc/c-api/float.rst

@@ -223,9 +223,6 @@ endian processor, or ``1`` on little endian processor.
 Return value: ``0`` if all is OK, ``-1`` if error (and an exception is set,
 most likely :exc:`OverflowError`).
 
-.. impl-detail::
-    The :c:func:`PyFloat_Pack8` function always succeeds in CPython.
-
 .. c:function:: int PyFloat_Pack2(double x, char *p, int le)
 
    Pack a C double as the IEEE 754 binary16 half-precision format.
@@ -238,6 +235,9 @@ most likely :exc:`OverflowError`).
 
    Pack a C double as the IEEE 754 binary64 double precision format.
 
+   .. impl-detail::
+       This function always succeeds in CPython.
+
 
 Unpack functions
 ^^^^^^^^^^^^^^^^