Tweak wording

Author: cpsievert

CHANGELOG.md

@@ -9,8 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### New features
 
-* The `Session` class gains a `current_output_id` attribute. If an output renderer is currently executing, this attribute will contain the relevant ID. (#1978)
 * The `.output_*()` methods of the `ClientData` class (e.g., `session.clientdata.output_height()`) can now be called without an `id` inside a output renderer. (#1978)
+* The `Session` class gains a `.current_output_id()` method. It returns the ID of the currently executing output renderer (if any). (#1978)
 
 ### Improvements
 

shiny/session/_session.py

@@ -1699,8 +1699,8 @@ def _read_output(self, id: str | None, key: str) -> str | None:
 
         if id is None:
             raise ValueError(
-                "session.clientdata.output_*() must be either be supplied with an id "
-                "or called from within an output renderer."
+                "session.clientdata.output_*() requires an id when not called within "
+                "an output renderer."
             )
 
         input_id = ResolvedId(f".clientdata_output_{id}_{key}")