Fix typo in custom models documentation
Author: anthonyylee
Pull request: yes

# What does this PR do?
The kwargs is expected to be `trust_remote_code` (ref: [`from_pretrained()` function source](https://github.com/huggingface/transformers/blob/57278c904c5158999d31a0db8bfcd63360c37b48/src/transformers/modeling_utils.py#L3902))

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## Before submitting
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Models:

- text models: @ArthurZucker @Cyrilvallez
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- graph models: @clefourrier

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- trainer: @SunMarc
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Comments:
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