style(core): lint (#34862)

it looks scary but i promise it is not

improving documentation consistency across core. primarily update
docstrings and comments for better formatting, readability, and
accuracy, as well as add minor clarifications and formatting
improvements to user-facing documentation.

libs/core/langchain_core/retrievers.py

@@ -1,4 +1,4 @@
-"""**Retriever** class returns Documents given a text **query**.
+"""**Retriever** class returns `Document` objects given a text **query**.
 
 It is more general than a vector store. A retriever does not need to be able to
 store documents, only to return (or retrieve) it. Vector stores can be used as
@@ -41,10 +41,13 @@ class LangSmithRetrieverParams(TypedDict, total=False):
 
     ls_retriever_name: str
     """Retriever name."""
+
     ls_vector_store_provider: str | None
     """Vector store provider."""
+
     ls_embedding_provider: str | None
     """Embedding provider."""
+
     ls_embedding_model: str | None
     """Embedding model."""
 
@@ -116,7 +119,9 @@ class BaseRetriever(RunnableSerializable[RetrieverInput, RetrieverOutput], ABC):
     )
 
     _new_arg_supported: bool = False
+
     _expects_other_args: bool = False
+
     tags: list[str] | None = None
     """Optional list of tags associated with the retriever.
 
@@ -126,6 +131,7 @@ class BaseRetriever(RunnableSerializable[RetrieverInput, RetrieverOutput], ABC):
     You can use these to eg identify a specific instance of a retriever with its
     use case.
     """
+
     metadata: dict[str, Any] | None = None
     """Optional metadata associated with the retriever.