Incorrect Javadoc comment in HttpTrigger.java

The following Javadoc describes the HttpTriger route method, but the sample described is incorrect and causes a compile error.

https://docs.microsoft.com/en-us/java/api/com.microsoft.azure.functions.annotation.httptrigger.route?view=azure-java-stable#com_microsoft_azure_functions_annotation_HttpTrigger_route__

The correct method type is `HttpResponseMessage`, not `HttpResponseMessage`.

```java
@FunctionName("routeTest")
public HttpResponseMessage routeTest(
@HttpTrigger(name = "req",
methods = {HttpMethod.GET},
authLevel = AuthorizationLevel.ANONYMOUS,
route = "products/{category:alpha}/{id:int}")
HttpRequestMessage> request,
@BindingName("category") String category,
@BindingName("id") int id,
final ExecutionContext context
) {
....
context.getLogger().info("We have " + category + " with id " + id);
....
}
```

This Javadoc is probably auto-generated from the following link.
Please fix it.

https://github.com/Azure/azure-functions-java-library/blob/dev/src/main/java/com/microsoft/azure/functions/annotation/HttpTrigger.java#L140