Fix PeftMixedModel example

[ringohoffman]

Feature request

The PeftMixedModel docstring references get_peft_model and imports it in its example but doesn't use it:

peft/src/peft/mixed_model.py

Lines 97 to 107 in ad8f7cb

	Example:
	```py
	>>> from peft import get_peft_model
	>>> base_model = ... # load the base model, e.g. from transformers
	>>> peft_model = PeftMixedModel.from_pretrained(base_model, path_to_adapter1, "adapter1").eval()
	>>> peft_model.load_adapter(path_to_adapter2, "adapter2")
	>>> peft_model.set_adapter(["adapter1", "adapter2"]) # activate both adapters
	>>> peft_model(data) # forward pass using both adapters
	```

Motivation

The unused import in the docstring is confusing.

Your contribution

Yes.

[BenjaminBossan]

Indeed, the import is not needed. Are you interested in creating a PR to fix the docstring?

[namanvats]

@BenjaminBossan Created a PR to fix the redundant import: #1850