fix(docs): imports and call (#7636)

Co-authored-by: Jacob Lee <[email protected]>

libs/langchain-anthropic/README.md

@@ -49,24 +49,30 @@ export ANTHROPIC_API_KEY=your-api-key
 Then initialize
 
 ```typescript
-import { ChatAnthropicMessages } from "@langchain/anthropic";
+import { ChatAnthropic } from "@langchain/anthropic";
 
 const model = new ChatAnthropic({
   apiKey: process.env.ANTHROPIC_API_KEY,
 });
-const response = await model.invoke(new HumanMessage("Hello world!"));
+const response = await model.invoke({
+  role: "user",
+  content: "Hello world!",
+});
 ```
 
 ### Streaming
 
 ```typescript
-import { ChatAnthropicMessages } from "@langchain/anthropic";
+import { ChatAnthropic } from "@langchain/anthropic";
 
 const model = new ChatAnthropic({
   apiKey: process.env.ANTHROPIC_API_KEY,
   model: "claude-3-sonnet-20240229",
 });
-const response = await model.stream(new HumanMessage("Hello world!"));
+const response = await model.stream({
+  role: "user",
+  content: "Hello world!",
+});
 ```
 
 ## Development
@@ -119,4 +125,4 @@ After running `yarn build`, publish a new version with:
 
 ```bash
 $ npm publish
-```
+```