add module as a default externs, specifically for transit-js
add module as a default externs, specifically for transit-js

gets rid of the annoying warning that module is undeclared.

fixes #919

thheller/shadow-cljs,thheller/shadow-devtools,thheller/shadow-devtools,thheller/shadow-cljs,thheller/shadow-devtools,thheller/shadow-devtools,thheller/shadow-cljs,thheller/shadow-cljs