fixup: remove space before \iref

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

Author: dietmarkuehl

source/exec.tex

@@ -6437,7 +6437,7 @@
 \pnum
 \effects
 If the signature \tcode{set_error_t(exception_ptr)} is not an element
-of \tcode{error_types}, calls \tcode{terminate()} \iref{except.terminate}.
+of \tcode{error_types}, calls \tcode{terminate()}\iref{except.terminate}.
 Otherwise, stores \tcode{current_exception()} into \exposid{errors}.
 \end{itemdescr}