Small aliases refactor.

[skratchdot]

I'm working on some code, and rather than including all my commits in one PR, I'd like to separate a few of the smaller, non-related fixes into their own PR's (for easier review).

Summary

Locally, I've upgraded my eslint versions, and the current aliases file throws lint errors due to the sort-keys rule. This commit fixes the errors by sorting all our keys. I kept the shorthands vs affordances separation by using 2 variables and the object spread syntax in the exported value.

Test plan

1. I made my changes then ran yarn build
2. I ran ./bin/yarn ls and a few other of the alias commands.
3. Confirmed that the behavior is the same before and after my changes.
4. Run yarn test
5. Confirm __tests__/cli/aliases.js has no errors
6. open ./coverage/lcov-report/index.html
7. Confirm that the coverage for src/cli/aliases.js is still 100%

[skratchdot]

NOTE: I didn't remove any values, all I did was re-order them. I also updated the flow syntax so the "string" values aren't optional. I can't ever see us adding an alias to a non-string command.

[bestander]

I don't think @kittens wanted to overload number of aliases for commands and I agree with him.
For example yarn list is short enough and if you use it a lot, it is easy to create your own shortcut on OS level.

[skratchdot]

@bestander - it still doesn't let you run yarn ls, it'll throw the error message: did you mean yarn list per:
https://github.com/yarnpkg/yarn/blob/master/src/cli/index.js#L126-L134

All I did was fix an eslint warning (which will happen if we ever upgrade our eslint versions).

[rjpcasalino]

@skratchdot I'm a fan of getting yarn i for install and was literally just thinking of adding that this morning. Anyway, thanks!

[bestander]

Ah, thanks for clearing up, @skratchdot!
Thanks.