Rename RegexProtocol to RegexComponent and RegexBuilder to RegexComponentBuilder.

[rxwei]

We've decided to use RegexComponent for the protocol, and use RegexComponentBuilder for the builder type since we want the user to import a module named RegexBuilder to get the DSL.

[milseman]

With this change, should String.match(_:) take a Regex instead?

One option is an ABI that takes Regex and an inlinable API that's generic and just passes off the static var. (I've also been wondering where the ABI falls for operating between generics and existential). WDYT?

[rxwei]

Sure. My main concern was not about ABI, but whether it makes sense to have matching API on a RegexComponent. As we sometimes want to use a custom regex component as a regex (to obtain its transformed Match), it seems like calling it "regex component" may not be entirely appropriate.

[milseman]

@natecook1000 how are option scopes and global options coming along? That might help clarify the relationship between a Regex, RegexProtocol, RegexComponent, etc.

[rxwei]

@swift-ci please test

[rxwei]

@swift-ci please test

[rxwei]

We converged on this solution in a meeting so I'll go ahead and merge. Any feedback is always welcome.