fix typo

vignettes/streaming-async.Rmd

@@ -46,7 +46,7 @@ coro::loop(for (chunk in stream) {
 
 ellmer also supports async usage. This is useful when you want to run multiple, concurrent chat sessions. This is particularly important for Shiny applications where using the methods described above would block the Shiny app for other users for the duration of each response.
 
-To use asyn chat, call `chat_async()`/`stream_async()` instead of `chat()`/`stream()`. The `_async` variants take the same arguments for construction but return a promise instead of the actual response.
+To use async chat, call `chat_async()`/`stream_async()` instead of `chat()`/`stream()`. The `_async` variants take the same arguments for construction but return a promise instead of the actual response.
 
 Remember that chat objects are stateful; they preserve the conversation history as you interact with it. This means that it doesn't make sense to issue multiple, concurrent chat/stream operations on the same chat object because the conversation history can become corrupted with interleaved conversation fragments. If you need to run concurrent chat sessions, create multiple chat objects.