Better docs for api_args (#101)

And actually use `extra_args` in gemini

Author: hadley

R/provider-gemini.R

@@ -84,11 +84,13 @@ method(chat_request, ProviderGemini) <- function(provider,
 
   contents <- gemini_contents(turns)
   tools <- gemini_tools(tools)
+  extra_args <- utils::modifyList(provider@extra_args, extra_args)
 
   body <- compact(list(
     contents = contents,
     tools = tools,
-    systemInstruction = system
+    systemInstruction = system,
+    !!!extra_args
   ))
   req <- req_body_json(req, body)
 

R/provider-openai.R

@@ -28,8 +28,8 @@ NULL
 #'   choosing a model for all but the most casual use.
 #' @param seed Optional integer seed that ChatGPT uses to try and make output
 #'   more reproducible.
-#' @param api_args Named list of arbitrary extra arguments passed to every
-#'   chat API call.
+#' @param api_args Named list of arbitrary extra arguments appended to the body
+#'   of every chat API call.
 #' @param echo One of the following options:
 #'   * `none`: don't emit any output (default when running in a function).
 #'   * `text`: echo text output as it streams in (default when running at