Fix R linting error

Author: nsoranzo

tools/join_files_by_id/join_files.R

@@ -57,7 +57,6 @@ df_list <- append(df0, df_list)
 df_list[[1]] <- data.frame(ids = df_list[[1]])
 
 
-
 ids <- df_list[[1]]
 ids <- data.frame(ids = ids[order(ids$ids), "ids"])
 merged_df <- mclapply(2:length(df_list), function(x) {