Keep names on @NestedSealed types (#413)

This ensures that the annotations themselves aren't stripped from the class descriptor and thus available at runtime.

moshi-sealed/runtime/src/main/resources/META-INF/proguard/moshi-sealed.pro

@@ -1,6 +1,10 @@
-# Keep NestedSealed for runtime use
+# Keep NestedSealed for runtime use.
 -keep interface dev.zacsweers.moshix.sealed.annotations.NestedSealed { *; }
 
+# Keep signatures for typed annotated with NestedSealed. This ensures that the annotation, while kept generally above,
+# isn't stripped from the use on the class.
+-keepnames @dev.zacsweers.moshix.sealed.annotations.NestedSealed class **
+
 # Keep generic signatures and annotations at runtime.
 # R8 requires InnerClasses and EnclosingMethod if you keepattributes Signature.
 -keepattributes InnerClasses,Signature,RuntimeVisible*Annotations,EnclosingMethod