message: Document main args in JIT mode
diff: @@ -53,6 +53,9 @@ Use the `-j` flag to compile and run the program immediately:
  $ bril2json < something.bril | brilift -j
  +Pass any arguments to the Bril `@main` function as command-line arguments to Brilift.
  +For example, if you have a function `@main(foo: int, bar: bool)`, you can type `brilift -j 42 true`.
  +
  Options
  -------
  