AST: Clean up ImportFilterKind comments.

NFC.

Author: tshortli

include/swift/AST/Module.h

@@ -934,16 +934,13 @@ class ModuleDecl
   enum class ImportFilterKind {
     /// Include imports declared with `@_exported`.
     Exported = 1 << 0,
-    /// Include "regular" imports with an access-level of `public`.
+    /// Include "regular" imports with an effective access level of `public`.
     Default = 1 << 1,
     /// Include imports declared with `@_implementationOnly`.
     ImplementationOnly = 1 << 2,
-    /// Include imports declared with `package import`.
+    /// Include imports declared with an access level of `package`.
     PackageOnly = 1 << 3,
-    /// Include imports marked `internal` or lower. These differs form
-    /// implementation-only imports by stricter type-checking and loading
-    /// policies. At this moment, we can group them under the same category
-    /// as they have the same loading behavior.
+    /// Include imports with an effective access level of `internal` or lower.
     InternalOrBelow = 1 << 4,
     /// Include imports declared with `@_spiOnly`.
     SPIOnly = 1 << 5,