experimental[patch]: update module doc strings (#19539)

Added missed module descriptions. Fixed format.

libs/experimental/langchain_experimental/open_clip/__init__.py

@@ -1,3 +1,11 @@
+"""**OpenCLIP Embeddings** model.
+
+OpenCLIP is a multimodal model that can encode text and images into a shared space.
+
+See this paper for more details: https://arxiv.org/abs/2103.00020
+and [this repository](https://github.com/mlfoundations/open_clip) for details.
+
+"""
 from .open_clip import OpenCLIPEmbeddings
 
 __all__ = ["OpenCLIPEmbeddings"]