fixup: fix speclling of exception_ptr and split the line

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

Author: dietmarkuehl

source/exceptions.tex

@@ -1129,7 +1129,8 @@
 whose promise type has an \tcode{unhandled_stopped} member function, or
 
 \item%
-when an exception is thrown from a coroutine \tcode{std::execution::task}\iref{exec.task} which doesn't support a \tcode{std::execution::set_error_t(std::execption_ptr)} completion.
+when an exception is thrown from a coroutine \tcode{std::execution::task}\iref{exec.task}
+which doesn't support a \tcode{std::execution::set_error_t(std::exception_ptr)} completion.
 
 \end{itemize}