fixup: remove space before \iref

Co-authored-by: Jan Schultke <[email protected]>

Author: dietmarkuehl

source/exec.tex

@@ -6347,7 +6347,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-An awaitable object of unspecified type \iref{expr.await} whose
+An awaitable object of unspecified type\iref{expr.await} whose
 member functions arrange for
 
 \begin{itemize}