docs: Improve docstring for Runnable bind method (#19659)

Added example to the docstring of the "bind" method of Runnable. This
makes it easier to understand the purpose of the method when reviewing
in code editors. E.g. VS Code below.

<img width="833" alt="Screenshot 2024-03-27 at 16 24 18"
src="https://github.com/langchain-ai/langchain/assets/45722942/ad022d4e-7bc0-4f4b-aa7a-838f1816cc52">

---------

Co-authored-by: Chester Curme <chester.curme@gmail.com>

libs/core/langchain_core/runnables/base.py

@@ -1336,6 +1336,37 @@ class Runnable(Generic[Input, Output], ABC):
     def bind(self, **kwargs: Any) -> Runnable[Input, Output]:
         """
         Bind arguments to a Runnable, returning a new Runnable.
+
+        Useful when a runnable in a chain requires an argument that is not
+        in the output of the previous runnable or included in the user input.
+
+        Example:
+
+        .. code-block:: python
+
+            from langchain_community.chat_models import ChatOllama
+            from langchain_core.output_parsers import StrOutputParser
+
+            llm = ChatOllama(model='llama2')
+
+            # Without bind.
+            chain = (
+                llm
+                | StrOutputParser()
+            )
+
+            chain.invoke("Repeat quoted words exactly: 'One two three four five.'")
+            # Output is 'One two three four five.'
+
+            # With bind.
+            chain = (
+                llm.bind(stop=["three"])
+                | StrOutputParser()
+            )
+
+            chain.invoke("Repeat quoted words exactly: 'One two three four five.'")
+            # Output is 'One two'
+
         """
         return RunnableBinding(bound=self, kwargs=kwargs, config={})