[res.on.arguments] Fix hyphenation of "move assignment"

Author: Eisenwave

source/lib-intro.tex

@@ -3360,7 +3360,7 @@
 \item
 If a function argument is bound to an rvalue reference parameter, the implementation may
 assume that this parameter is a unique reference to this argument,
-except that the argument passed to a move-assignment operator may be
+except that the argument passed to a move assignment operator may be
 a reference to \tcode{*this}\iref{lib.types.movedfrom}.
 \begin{note}
 If the type of a parameter is a forwarding reference\iref{temp.deduct.call}