fix: 2errors in adding in topics langchain core:1.has matching logo should not specify logo langchain.png when file does not exist 2. Use open source without a hyphen.

Author: hamsehmahamud

topics/langchain/index.md

@@ -3,11 +3,10 @@ aliases: langchain-core
 created_by: hwchase17
 display_name: LangChain
 github_url: https://github.com/langchain-ai/langchain
-logo: langchain.png
 related: artificial-intelligence, llm, prompt-engineering, rag, agents
 short_description: LangChain is an open-source framework designed to simplify the creation of applications using large language models.
 topic: langchain
 url: https://www.langchain.com/
 wikipedia_url: https://en.wikipedia.org/wiki/LangChain
 ---
-LangChain is an open-source orchestration framework designed to help developers build context-aware, reasoning applications powered by large language models (LLMs). It provides modular abstractions for document loaders, vector stores, prompt templates, and autonomous agent workflows.
+LangChain is an open source orchestration framework designed to help developers build context-aware, reasoning applications powered by large language models (LLMs). It provides modular abstractions for document loaders, vector stores, prompt templates, and autonomous agent workflows.