[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/nougat.md

@@ -33,7 +33,7 @@ alt="drawing" width="600"/>
 This model was contributed by [nielsr](https://huggingface.co/nielsr). The original code can be found
 [here](https://github.com/facebookresearch/nougat).
 
-Tips:
+## Usage tips
 
 - The quickest way to get started with Nougat is by checking the [tutorial
   notebooks](https://github.com/NielsRogge/Transformers-Tutorials/tree/master/Nougat), which show how to use the model
@@ -89,6 +89,12 @@ into a single instance to both extract the input features and decode the predict
 
 See the [model hub](https://huggingface.co/models?filter=nougat) to look for Nougat checkpoints.
 
+<Tip>
+
+The model is identical to [Donut](donut) in terms of architecture.
+
+</Tip>
+
 ## NougatImageProcessor
 
 [[autodoc]] NougatImageProcessor