core: docstrings shouldn't inherit from parents

from langchain_core.tools import tool
from pydantic import BaseModel


class MyTool(BaseModel):
    """Parent Tool"""
    foo: str

@tool
class ChildTool(MyTool):
    bar: str

For 0.4 release we could consider updating the behavior so that doc-strings are not inherited from their parents. It's fairly odd that doc-strings are inherited for BaseModels as in general the descriptions need to be different

Originally posted by @eyurtsev in #31606