Say what ought to happen when running rustup doc. #3663
Description
Problem you are trying to solve
On macOS.
I ran "rustup doc --book" on my command line. It returned, and nothing appeared to happen. Something did happen, the site is open on my browser, but I use desktops, and it doesn't raise things quite correctly (not rust's problem).
If you are new to Rust consider running `rustup doc --book` to
learn Rust.
✔ ~/src/CatHerd [master|✚ 1…2]
14:01 $ rustup doc --book
✔ ~/src/CatHerd [master|✚ 1…2]
Solution you'd like
if the thing had printed "Opening the Rust Book in your browser", I would have slid over there, and all would be good.
Notes
No response