docs[patch]: update installation with core and community (#14577)

docs/docs/get_started/installation.mdx

@@ -29,6 +29,20 @@ If you want to install from source, you can do so by cloning the repo and be sur
 pip install -e .
 ```
 
+## LangChain community
+The `langchain-community` package contains third-party integrations. It is automatically installed by `langchain`, but can also be used separately. Install with:
+
+```bash
+pip install langchain-community
+```
+
+## LangChain core
+The `langchain-core` package contains base abstractions that the rest of the LangChain ecosystem uses, along with the LangChain Expression Language. It is automatically installed by `langchain`, but can also be used separately. Install with:
+
+```bash
+pip install langchain-core
+```
+
 ## LangChain experimental
 The `langchain-experimental` package holds experimental LangChain code, intended for research and experimental uses.
 Install with:
@@ -61,4 +75,4 @@ If not using LangChain, install with:
 
 ```bash
 pip install langsmith
-```
+```