Move corpus composition description to captions

Change-Id: Ie0d3de5218693ddd67da85f3b096d95efb87abb2
diff --git a/R/poster.Rmd b/R/poster.Rmd
index 56703b9..3c435e5 100644
--- a/R/poster.Rmd
+++ b/R/poster.Rmd
@@ -102,9 +102,8 @@
 ![](korap_query.png) 
 
 ## Composition of the ICC parts 
-### By ICC genre
 
-```{r composition_by_genre, message = FALSE, fig.width=14, fig.height=10, out.width = "100%"}
+```{r composition-by-genre, fig.cap="Actual composition of selected ICC parts with respect to ICC domain. (For the other ICC parts, the ICC genre metadatum was not yet accessible via the API at the editorial deadline.)", message = FALSE, fig.width=14, fig.height=10, out.width = "100%"}
 icc_genre <- icc %>%
   expand_grid(genre) %>%
   mutate(vc = paste0("iccGenre=", genre)) %>%
@@ -125,10 +124,8 @@
 
 ```
 
-### By date of publication
 
-
-```{r composition-by-pubdate, message=F, warning=F, fig.width=14, fig.height=3, out.width = "80%"}
+```{r composition-by-pubdate, fig.cap="Composition of the selected ICC parts with respect to year of publication.", message=F, warning=F, fig.width=14, fig.height=3, out.width = "80%"}
 year <- c(1986:2023)
 
 icc_year <- icc %>%