[Docs] Model_doc structure/clarity improvements (#26876)

* first batch of structure improvements for model_docs

* second batch of structure improvements for model_docs

* more structure improvements for model_docs

* more structure improvements for model_docs

* structure improvements for cv model_docs

* more structural refactoring

* addressed feedback about image processors

docs/source/en/model_doc/bertweet.md

@@ -28,7 +28,9 @@ al., 2019). Experiments show that BERTweet outperforms strong baselines RoBERTa-
 2020), producing better performance results than the previous state-of-the-art models on three Tweet NLP tasks:
 Part-of-speech tagging, Named-entity recognition and text classification.*
 
-Example of use:
+This model was contributed by [dqnguyen](https://huggingface.co/dqnguyen). The original code can be found [here](https://github.com/VinAIResearch/BERTweet).
+
+## Usage example
 
 ```python
 >>> import torch
@@ -55,7 +57,12 @@ Example of use:
 >>> # bertweet = TFAutoModel.from_pretrained("vinai/bertweet-base")
 ```
 
-This model was contributed by [dqnguyen](https://huggingface.co/dqnguyen). The original code can be found [here](https://github.com/VinAIResearch/BERTweet).
+<Tip> 
+
+This implementation is the same as BERT, except for tokenization method. Refer to [BERT documentation](bert) for 
+API reference information.  
+
+</Tip>
 
 ## BertweetTokenizer