[Process] Mention constructor's default 60s timeout

[dharkness]

This line from the documentation implies that there is no timeout unless you set one yourself.

You can limit the amount of time a process takes to complete by setting a timeout.

I recommend adding a warning about the default 60s timeout to that section. I would prefer removing the default timeout altogether, but that's probably a non-starter as a breaking change.

[javiereguiluz]

Fixed by #10472.