Update submission instructions for m1.

Author: dvanhorn

www/midterms/1.scrbl

@@ -24,7 +24,7 @@ If you have questions about the exam, send a DM to ModMail on Discord.
 This will go to the entire course staff.
 
 Answers to common clarifying questions will be posted to the
-@tt{#midterm-1} channel on Discord.
+@tt{#midterm1} channel on Discord.
 
 If you have trouble reaching the course staff via Discord, email
 @tt{@prof-email}.
@@ -35,6 +35,14 @@ the midterm.
 @section{Submissions}
 
 You should submit your work as a single zip file of this directory on
-Gradescope.  Unlike past assignments, Gradescope will not provide
-feedback on the correctness of your solutions so you are encouraged to
-check your own work.
+Gradescope.  Unlike past assignments, Gradescope will only do a basic
+test for well-formedness of your submission.  It will make sure the
+directory layout is correct and that all the functions that will be
+tested are available.  It will catch syntax errors in your code, but
+it does not run any correctness tests.
+
+If you fail these tests, we will not be able to grade your submission.
+Passing these tests only means your submission is well-formed.  Your
+actual grade will be computed after the deadline.
+
+You are encouraged to check your own work.