Small grammar fix, thanks Sjoerd.

 (backport from rev. 52311)

Doc/lib/libfpectl.tex

@@ -8,7 +8,7 @@
 \modulesynopsis{Provide control for floating point exception handling.}
 
 \note{The \module{fpectl} module is not built by default, and its usage
-      is discouraged and may be dangerous except in the hand of
+      is discouraged and may be dangerous except in the hands of
       experts.  See also the section \ref{fpectl-limitations} on
       limitations for more details.}