Improve 1991/westley/ttt.sh

Make it so that the warnings/errors (i.e. stderr) of the compilation (as
well as the echo saying it's going to compile) not show unless -e is
used. This is because the warnings kind of ruin the experience.

Updated README.md to explain this.

1991/westley/README.md

@@ -107,6 +107,8 @@ c(1);*J=--u?O?*J:*v[1]:53;X|=u<<57-*v[u];y(X);K=40+q;q?e(O,X),q&&(K='|'),e(X
 ttt: I win!
 ```
 
+Redirects stderr to `/dev/null` by default. If you need errors or warnings use
+`-e`.
 
 ## Judges' remarks: