fixup: use proper indentation after template head

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

Author: dietmarkuehl

source/exec.tex

@@ -5940,7 +5940,7 @@
 
 \begin{itemdecl}
 template<@\libconcept{receiver}@ Rcvr>
-@\exposid{state}@<Rcvr> connect(Rcvr&& rcvr);
+  @\exposid{state}@<Rcvr> connect(Rcvr&& rcvr);
 \end{itemdecl}
 
 \pnum