rust-chg: reimplement run_command operation as async function
The crafted state machine is no longer needed thanks to async/await.
The state machine is basically rewritten as follows:
- Ready(..) -> return ..
- PollAgain(..) -> run .. and await
- Err(..) -> return Err(..)
Differential Revision: https://phab.mercurial-scm.org/D8445
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}