Make ActionResult handling behind EnableActionResultHandling the default in 3.0

[fabiocav]

For backwards compatibility reasons, some ActionResult handling enhancements added to 2.0 had to be placed behind a feature flag (EnableActionResultHandling).

We may want to consider a flag to maintain the 2.0 behavior if we believe that would ease migration, but the behavior behind the flag should be the default in 3.0.

[brettsam]

@fabiocav -- what's the deal with this proposal? Is this something we could/should do in v4?

[ericsampson]

@fabiocav -- what's the deal with this proposal? Is this something we could/should do in v4?

yes please. Along with making DisableDevModeInDebug the default behavior as well.

[fabiocav]

Will create breaking change proposals for both items.

[ericsampson]

Is EnableEnhancedScopes getting rolled out by default soon? That one seems more of a bug fix than change, I can't see people wanting the original behavior.