[FixCode] Add @escaping when overriding mismatch is because of it.

[nkcsgexi]

[FixCode] Add @escaping when overriding mismatch is because of it. rdar://27814862

• Explanation: With the change of default escaping behavior, users' existing code overriding
  objc functions may need to add @escaping to make the overriding match as before. This
  patch checks if an overriding mismatch is due to the lacking of @escaping and add
  it as a fixit.
• Scope of issue: One fixit in overriding.
• Reviewer: @jrose-apple
• Risk: Low
• Radar: rdar://27814862

[nkcsgexi]

@swift-ci Please test OS X platform

[najacque]

@swift-ci Please ignore

[FixCode] Add @escaping when overriding mismatch is because of it. rdar://27814862

Explanation: With the change of default escaping behavior, users' existing code overriding
objc functions may need to add @escaping to make the overriding match as before. This
patch checks if an overriding mismatch is due to the lacking of @escaping and add
it as a fixit.

Scope of issue: One fixit in overriding.

Reviewer: @jrose-apple

Risk: Low

Radar: rdar://27814862

[najacque]

@swift-ci Please nominate

[FixCode] Add @escaping when overriding mismatch is because of it. rdar://27814862

Explanation: With the change of default escaping behavior, users' existing code overriding
objc functions may need to add @escaping to make the overriding match as before. This
patch checks if an overriding mismatch is due to the lacking of @escaping and add
it as a fixit.

Scope of issue: One fixit in overriding.

Reviewer: @jrose-apple

Risk: Low

Radar: rdar://27814862