docs: ExperimentRun docstring and end_run kwarg (#1649)

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Author: jaycee-li

google/cloud/aiplatform/metadata/experiment_run_resource.py

@@ -104,7 +104,8 @@ def __init__(
         ```
 
         Args:
-            run (str): Required. The name of this run.
+            run_name (str):
+                Required. The name of this run.
             experiment (Union[experiment_resources.Experiment, str]):
                 Required. The name or instance of this experiment.
             project (str):
@@ -1059,7 +1060,7 @@ def __exit__(self, exc_type, exc_value, traceback):
         if metadata._experiment_tracker.experiment_run is self:
             metadata._experiment_tracker.end_run(state=state)
         else:
-            self.end_run(state)
+            self.end_run(state=state)
 
     def end_run(
         self,