Fix small typo in roxygen for google_font

Just a very small typo I stumbled upon while reading the help. :)

R/utils.R

 #' Specify Google Font
 #'
 #' Builds Google Fonts URL from family name. Extra weights are given in the
-#' `...` parameters. Languages can be specified in `langauges` and must one or
+#' `...` parameters. Languages can be specified in `languages` and must one or
 #' more of the language codes as given by `google_language_codes()`.
 #'
 #' @examples