fix: wrong uv commands

src/oss/langchain/install.mdx

@@ -17,7 +17,7 @@ To install the core LangChain package:
     ```
 
     ```bash uv
-    uv add langchain@pre
+    uv add --prerelease=allow langchain
     ```
 </CodeGroup>
 :::

src/oss/langchain/overview.mdx

@@ -37,7 +37,7 @@ pip install --pre -U langchain
 ```
 
 ```bash uv
-uv add langchain@pre
+uv add --prerelease=allow langchain
 ```
 </CodeGroup>
 :::

src/oss/langgraph/install.mdx

@@ -16,7 +16,7 @@ pip install --pre -U langgraph
 ```
 
 ```bash uv
-uv add langgraph@pre
+uv add --prerelease=allow langgraph
 ```
 </CodeGroup>
 :::
@@ -55,7 +55,7 @@ pip install --pre -U langchain
 ```
 
 ```bash uv
-uv add langchain@pre
+uv add --prerelease=allow langchain
 ```
 </CodeGroup>
 :::

src/oss/langgraph/overview.mdx

@@ -23,7 +23,7 @@ pip install --pre -U langgraph
 ```
 
 ```bash uv
-uv add langgraph@pre
+uv add --prerelease=allow langgraph
 ```
 </CodeGroup>
 :::