A reStructured Text (RST) file is a file format for textual data used primarily in the Python programming language community for technical documentation.

​
UnstructuredRSTLoader

You can load data from RST files with UnstructuredRSTLoader using the following workflow. 
from langchain_community.document_loaders import UnstructuredRSTLoader

loader = UnstructuredRSTLoader(file_path="./example_data/README.rst", mode="elements")
docs = loader.load()

print(docs[0])

page_content='Example Docs' metadata={'source': './example_data/README.rst', 'category_depth': 0, 'last_modified': '2023-12-19T13:42:18', 'languages': ['eng'], 'filetype': 'text/x-rst', 'file_directory': './example_data', 'filename': 'README.rst', 'category': 'Title'}