correct TTS pipeline docstrings snippet (#25587)

* correct TTS pipeline docstrings snippet

* add text_to_audio.py pipelines to documentation tests

src/transformers/pipelines/text_to_audio.py

@@ -34,8 +34,8 @@ class TextToAudioPipeline(Pipeline):
     ```python
     >>> from transformers import pipeline
 
-    >>> classifier = pipeline(model="suno/bark")
-    >>> output = pipeline("Hey it's HuggingFace on the phone!")
+    >>> pipe = pipeline(model="suno/bark-small")
+    >>> output = pipe("Hey it's HuggingFace on the phone!")
 
     >>> audio = output["audio"]
     >>> sampling_rate = output["sampling_rate"]

utils/documentation_tests.txt

@@ -489,3 +489,4 @@ src/transformers/models/yolos/image_processing_yolos.py
 src/transformers/models/yolos/modeling_yolos.py
 src/transformers/models/yoso/configuration_yoso.py
 src/transformers/pipelines/
+src/transformers/pipelines/text_to_audio.py
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