ella: refresh README and mkdocs

Follow up of #389

README.md

@@ -31,6 +31,7 @@ ______________________________________________________________________
 
 ## Latest News 🔥
 
+- Added [ELLA](https://arxiv.org/abs/2403.05135) for better prompts handling (contributed by [@ily-R](https://github.com/ily-R))
 - Added the Box Segmenter all-in-one solution ([model](https://huggingface.co/finegrain/finegrain-box-segmenter), [HF Space](https://huggingface.co/spaces/finegrain/finegrain-object-cutter))
 - Added [MVANet](https://arxiv.org/abs/2404.07445) for high resolution segmentation
 - Added [IC-Light](https://github.com/lllyasviel/IC-Light) to manipulate the illumination of images

docs/reference/foundationals/latent_diffusion.md

@@ -15,3 +15,5 @@
 ::: refiners.foundationals.latent_diffusion.style_aligned
 
 ::: refiners.foundationals.latent_diffusion.multi_diffusion
+
+::: refiners.foundationals.latent_diffusion.ella_adapter

src/refiners/foundationals/latent_diffusion/ella_adapter.py

@@ -210,6 +210,11 @@ class PerceiverResampler(fl.Chain):
 
 
 class ELLA(fl.Passthrough):
+    """ELLA latents encoder.
+
+    See [[arXiv:2403.05135] ELLA: Equip Diffusion Models with LLM for Enhanced Semantic Alignment](https://arxiv.org/abs/2403.05135) for more details.
+    """
+
     def __init__(
         self,
         time_channel: int,
@@ -249,6 +254,8 @@ class ELLACrossAttentionAdapter(fl.Chain, Adapter[fl.UseContext]):
 
 
 class ELLAAdapter(Generic[T], fl.Chain, Adapter[T]):
+    """Adapter for [`ELLA`][refiners.foundationals.latent_diffusion.ella_adapter.ELLA]."""
+
     def __init__(self, target: T, latents_encoder: ELLA, weights: dict[str, Tensor] | None = None) -> None:
         if weights is not None:
             latents_encoder.load_state_dict(weights)

src/refiners/foundationals/latent_diffusion/stable_diffusion_1/ella_adapter.py

@@ -5,7 +5,15 @@ from refiners.foundationals.latent_diffusion.stable_diffusion_1.unet import SD1U
 
 
 class SD1ELLAAdapter(ELLAAdapter[SD1UNet]):
+    """[`ELLA`][refiners.foundationals.latent_diffusion.ella_adapter.ELLA] adapter for Stable Diffusion 1.5."""
+
     def __init__(self, target: SD1UNet, weights: dict[str, Tensor] | None = None) -> None:
+        """Initialize the adapter.
+
+        Args:
+            target: The target model to adapt.
+            weights: The weights of the ELLA adapter (see `scripts/conversion/convert_ella_adapter.py`).
+        """
         latents_encoder = ELLA(
             time_channel=320,
             timestep_embedding_dim=768,