Update R/auth.R

Co-authored-by: brookslogan <lcbrooks@cs.cmu.edu>

Author: dshemetov

R/auth.R

@@ -11,11 +11,12 @@
 #' key](https://api.delphi.cmu.edu/epidata/admin/registration_form).
 #'
 #' API keys are strings read from the environment variable `DELPHI_EPIDATA_KEY`.
-#' We recommend setting your key with `save_api_key()`, which will modify your
-#' `.Renviron` file and will persist your key across R sessions (see `?Startup`
-#' for a description of `.Renviron` files). Alternatively, you can modify the
-#' environment variable in the shell or with `Sys.setenv()`, but these will not
-#' persist across sessions.
+#' We recommend setting your key with `save_api_key()`, which will modify an
+#' applicable `.Renviron` file, which will be read in automatically when you
+#' start future R sessions (see [`?Startup`][base::Startup] for details on
+#' `.Renviron` files). Alternatively, you can modify the environment variable at
+#' the command line before/while launching R, or inside an R session with
+#' [`Sys.setenv()`], but these will not persist across sessions.
 #'
 #' Once an API key is set, it is automatically used for all requests made by
 #' functions in this package.