[3.14] Update NaNs handling description in c-api/float.rst (GH-141179) (#141194)

Update NaNs handling description in `c-api/float.rst` (GH-141179)

Clarified the behavior of NaNs on IEEE platforms regarding signaling and quiet NaNs.
(cherry picked from commit 920286d)

Co-authored-by: W. H. Wang <mattwang44@gmail.com>

Author: miss-islington

Doc/c-api/float.rst

@@ -113,8 +113,8 @@ NaNs (if such things exist on the platform) isn't handled correctly, and
 attempting to unpack a bytes string containing an IEEE INF or NaN will raise an
 exception.
 
-Note that NaNs type may not be preserved on IEEE platforms (silent NaN become
-quiet), for example on x86 systems in 32-bit mode.
+Note that NaNs type may not be preserved on IEEE platforms (signaling NaN become
+quiet NaN), for example on x86 systems in 32-bit mode.
 
 On non-IEEE platforms with more precision, or larger dynamic range, than IEEE
 754 supports, not all values can be packed; on non-IEEE platforms with less