Fix typos in ellmer.Rmd (#253)

vignettes/ellmer.Rmd

@@ -81,7 +81,7 @@ Writing a good prompt, which is called __prompt design__, is key to effective us
 
 Now that you've got the basic vocab under your belt, I'm going to fire a bunch of interesting potential use cases at you. While there are special purpose tools that might solve these cases faster and/or cheaper, an LLM allows you to rapidly prototype a solution. This can be extremely valuable even if you end up using those more specialised tools in your final product.
 
-In general, we recommend avoiding LLMs where accuracy is critical. That said, there are still many cases for their use. For example, even though they always requires some manual fiddling, you might save a bunch of time evern with an 80% correct solution. In fact, even a not-so-good solution can still be useful because it makes it easier to get started: it's easier to react to something rather than to have to start from scratch with a blank page.
+In general, we recommend avoiding LLMs where accuracy is critical. That said, there are still many cases for their use. For example, even though they always require some manual fiddling, you might save a bunch of time ever with an 80% correct solution. In fact, even a not-so-good solution can still be useful because it makes it easier to get started: it's easier to react to something rather than to have to start from scratch with a blank page.
 
 ### Chatbots