Deduplicate nodes in docstring (#2110)

Summary:
Pull Request resolved: #2110

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Created from CodeHub with https://fburl.com/edit-in-codehub

Reviewed By: Balandat

Differential Revision: D52372382

fbshipit-source-id: abe31be3309257bd5cd7da64d39ac5dc3398fee2

ax/modelbridge/generation_strategy.py

@@ -80,9 +80,6 @@ class GenerationStrategy(GenerationStrategyInterface):
     described in the `trials_per_model` argument.
 
     Args:
-        nodes: A list of `GenerationNode` describing a graphical representation
-            of the generation strategy. Either, but not both, of `nodes` and `steps`
-            must be provided.
         nodes: A list of `GenerationNode`. Each `GenerationNode` in the list
             represents a single node in a `GenerationStrategy` which, when
             composed of `GenerationNodes`, can be conceptualized as a graph instead