[futures.async] Reduce spacing after INVOKE, DECAY_COPY

See also 025f115 and #1510.

Author: tkoeppe

source/threads.tex

@@ -4813,8 +4813,8 @@
 satisfy the
 \tcode{MoveConstructible} requirements, and
 \begin{codeblock}
-@\placeholder{INVOKE}@(@\placeholder{DECAY_COPY}@(std::forward<F>(f)),
-       @\itcorr[1]\placeholder{DECAY_COPY}@(std::forward<Args>(args))...)  // see \ref{func.require}, \ref{thread.thread.constr}
+@\placeholdernc{INVOKE}@(@\placeholdernc{DECAY_COPY}@(std::forward<F>(f)),
+       @\placeholdernc{DECAY_COPY}@(std::forward<Args>(args))...)     // see \ref{func.require}, \ref{thread.thread.constr}
 \end{codeblock}
 shall be a valid expression.