* doc/lispref/processes.texi (Sentinels): Place . after @xref.
This makes it possible to use the Lisp debugger to debug the
sentinel. @xref{Debugger}. If an error is caught, Emacs pauses for
@code{process-error-pause-time} seconds so that the user sees the
-error. @xref{Asynchronous Processes}
+error. @xref{Asynchronous Processes}.
While a sentinel is running, the process sentinel is temporarily
set to @code{nil} so that the sentinel won't run recursively.