updated README

.cross_sync/README.md

@@ -47,10 +47,10 @@ Additionally, CrossSync provides method implementations that work equivalently i
 CrossSync provides a set of annotations to mark up async classes, to guide the generation of sync code.
 
 - `@CrossSync.export_sync`
-  - marks classes for conversion, along with an output file path
+  - marks classes for conversion. Unmarked classes will be droppd
   - if add_mapping is included, the async and sync classes can be accessed using a shared CrossSync.X alias
 - `@CrossSync.convert`
-  - marks async functions for conversion
+  - marks async functions for conversion. Unmarked methods will be copied as-is
 - `@CrossSync.drop_method`
   - marks functions that should not be included in sync output
 - `@CrossSync.pytest`