hc_freq_by_year_ci: allow additional parameters passed to hc_add_series

for example:

new("KorAPConnection", verbose=T) %>%
  frequencyQuery('[orth="Corona-?[vV]ir.*"]',
      paste("textType = /Zeit.*/ & creationDate in", (2000:2018))) %>%
  hc_freq_by_year_ci(
    dataLabels = list(
    enabled = TRUE,
    format = "({point.count})"
    )
  )

Change-Id: I1a393d2ea97907d5580f072cf6b2d27b1523ffbb
diff --git a/R/highcharter-helper.R b/R/highcharter-helper.R
index a78f57c..4c40a92 100644
--- a/R/highcharter-helper.R
+++ b/R/highcharter-helper.R
@@ -9,6 +9,7 @@
 #' @param df data frame like the value of a \code{\link{frequencyQuery}}
 #' @param as.alternatives boolean decides whether queries should be treated as mutually exclusive and exhaustive wrt. to some meaningful class (e.g. spelling variants of a certain word form).
 #' @param ylabel defaults to \% if \code{as.alternatives} is \code{true} and to "ipm" otherwise.
+#' @param ... additional arguments passed to \code{\link{hc_add_series}}
 #'
 #' @examples
 #' \donttest{year <- c(1990:2018)}\dontshow{year <- c(2013:2013)}
@@ -33,7 +34,7 @@
 #'   hc_freq_by_year_ci()
 #' }
 #'
-hc_freq_by_year_ci <- function(df, as.alternatives = FALSE, ylabel = if(as.alternatives) "%" else "ipm") {
+hc_freq_by_year_ci <- function(df, as.alternatives = FALSE, ylabel = if(as.alternatives) "%" else "ipm", ...) {
   title <- ""
   df <- df %>%
     { if(! as.alternatives) ipm(.) else RKorAPClient::percent(.) }
@@ -95,13 +96,13 @@
       shared = TRUE,
       valueSuffix = paste0('\U2009', ylabel)
     ) %>%
-    hc_add_series_korap_frequencies(df, as.alternatives)
+    hc_add_series_korap_frequencies(df, as.alternatives, ...)
 }
 
 ## Mute notes: "no visible binding for global variable:"
 globalVariables(c("value", "query", "condition", "vc"))
 
-hc_add_series_korap_frequencies <- function(hc, df, as.alternatives = FALSE) {
+hc_add_series_korap_frequencies <- function(hc, df, as.alternatives = FALSE, ...) {
   index <- 0
   for(q in unique(df$condition)) {
     dat <- df[df$condition==q,]
@@ -117,7 +118,8 @@
       hcaes(year, value),
       type = 'line',
       colorIndex = index,
-      zIndex = 1
+      zIndex = 1,
+      ...
     ) %>%
       hc_add_series(
         name = "ci",
diff --git a/man/hc_freq_by_year_ci.Rd b/man/hc_freq_by_year_ci.Rd
index 273b06f..8e963fe 100644
--- a/man/hc_freq_by_year_ci.Rd
+++ b/man/hc_freq_by_year_ci.Rd
@@ -7,7 +7,8 @@
 hc_freq_by_year_ci(
   df,
   as.alternatives = FALSE,
-  ylabel = if (as.alternatives) "\%" else "ipm"
+  ylabel = if (as.alternatives) "\%" else "ipm",
+  ...
 )
 }
 \arguments{
@@ -16,6 +17,8 @@
 \item{as.alternatives}{boolean decides whether queries should be treated as mutually exclusive and exhaustive wrt. to some meaningful class (e.g. spelling variants of a certain word form).}
 
 \item{ylabel}{defaults to \% if \code{as.alternatives} is \code{true} and to "ipm" otherwise.}
+
+\item{...}{additional arguments passed to \code{\link{hc_add_series}}}
 }
 \description{
 Experimental convenience function for plotting typical frequency by year graphs with confidence intervals using highcharter.