Add strict typehinting to edge

[danepowell]

I consider strict typehinting to be a best practice. We should adopt this in all of our projects. I'm adding this to edge since it's a heavy lift to adopt for existing projects without typehinting.

It might be such a large effort that we want to put it in a standalone "StrictTypes" standard or something.

I think there's also a Slevomat sniff to enforce the use of declare(strict_types=1) in every file, if we want to take it that far.

[TravisCarden]

I consider strict typehinting to be a best practice. We should adopt this in all of our projects.

I'm on board!

I think there's also a Slevomat sniff to enforce the use of declare(strict_types=1) in every file, if we want to take it that far.

For posterity, that would be SlevomatCodingStandard.TypeHints.DeclareStrictTypes.

It might be such a large effort that we want to put it in a standalone "StrictTypes" standard or something.

Yeah. In fact, as you point out, even parameter/property/return type hints could be a big lift for some projects. What if we do this?

1. Merge this PR as-is.
2. Cut a final release on the 1.x branch, e.g., v1.1.0.
3. Create a new major version branch (2.x) and merge AcquiaEdge into AcquiaDrupalStrict.
4. Add SlevomatCodingStandard.TypeHints.DeclareStrictTypes to the now-empty AcquiaEdge.
5. Get feedback from users on how difficult the new rule it would be to adopt and decide accordingly when and whether to merge it into AcquiaDrupalStrict.

[danepowell]

Let's do it! I'll merge this and see if I remember how to cut a release, I'll let you handle the comms, or maybe it needs to go through the ORCA team since ORCA will need to bump the coding standards to v2 at some point.

[danepowell]

v1.1.0 is out: https://github.com/acquia/coding-standards-php/releases/tag/v1.1.0