[exec.on] Add \tcode for sch

Author: Andreas-Krug

source/exec.tex

@@ -3277,7 +3277,7 @@
 remember the current scheduler, \tcode{get_scheduler(get_env(rcvr))};
 \item
 start \tcode{sndr} on an execution agent belonging to
-sch's associated execution resource;
+\tcode{sch}'s associated execution resource;
 \item
 upon \tcode{sndr}'s completion,
 transfer execution back to the execution resource
@@ -3312,7 +3312,7 @@
 \item
 upon \tcode{sndr}'s completion,
 transfer execution to an agent
-owned by sch's associated execution resource;
+owned by \tcode{sch}'s associated execution resource;
 \item
 forward \tcode{sndr}'s async result as if by
 connecting and starting a sender \tcode{closure(S)},