mistralai[patch]: Fix Typos in Comments and Improve Compatibility Note (#31616)

Description:  
This pull request corrects minor spelling mistakes in the comments
within the `chat_models.py` file of the MistralAI partner integration.
Specifically, it fixes the spelling of "equivalent" and "compatibility"
in two separate comments. These changes improve code readability and
maintain professional documentation standards. No functional code
changes are included.

Author: zeevick10

libs/partners/mistralai/langchain_mistralai/chat_models.py

@@ -83,7 +83,7 @@
 TOOL_CALL_ID_PATTERN = re.compile(r"^[a-zA-Z0-9]{9}$")
 
 
-# This SSL context is equivelent to the default `verify=True`.
+# This SSL context is equivalent to the default `verify=True`.
 # https://www.python-httpx.org/advanced/ssl/#configuring-client-instances
 global_ssl_context = ssl.create_default_context(cafile=certifi.where())
 
@@ -592,7 +592,7 @@ def _create_chat_result(self, response: dict) -> ChatResult:
         llm_output = {
             "token_usage": token_usage,
             "model_name": self.model,
-            "model": self.model,  # Backwards compatability
+            "model": self.model,  # Backwards compatibility
         }
         return ChatResult(generations=generations, llm_output=llm_output)