[docs] CToSwift: CF types (how they're recognized + dropping "Ref")

Author: jrose-apple

docs/CToSwiftNameTranslation.md

@@ -195,4 +195,15 @@ extension SecretResourceID {
 
 On Apple platforms, whenever Foundation is imported, constants with the type "NSNotificationName" additionally have the suffix "Notification" stripped before performing the above rules unless they have a custom name. Global NSString constants whose name ends in "Notification" will also automatically be treated as if they were declared with the type NSNotificationName unless they have a custom name.
 
+
+## CF Types
+
+"Core Foundation" is a C-based object-oriented system with strong conventions built around pointers to opaque structs. Creating new Core Foundation types is not generally supported, but Swift will recognize those in Apple's SDKs. If a struct has the `objc_bridge`, `objc_mutable_bridge`, or `objc_bridge_related` Clang attributes, it will be treated as a CF type and a typedef of a pointer to that struct will be imported as a class in Swift. The suffix "Ref" will be dropped from the class's name if present unless doing so would conflict with another declaration in the same module as the typedef.
+
+If the class name contains the word "Mutable" exactly once per the usual word-boundary rules, a corresponding class name without the word "Mutable" will be used as the superclass if present. Otherwise, the CF type is taken to be a root object.
+
+Additionally, typedefs for `void *` or `const void *` that are themselves annotated with `objc_bridge` will be treated as CFTypeRef-like and imported as `Any` rather than `Unsafe[Mutable]RawPointer`.
+
+If a typedef's underlying type is itself a "CF pointer" typedef, the "alias" typedef will be imported as a regular typealias, with the suffix "Ref" still dropped from its name (if present) unless doing so would conflict with another declaration in the same module as the typedef.
+
 ## More to come...