add descriptions to language statistics page

pages/1_Language_Statistics.py

@@ -12,6 +12,22 @@ def get_language_stats_df():
 st.set_page_config(page_title="Language Statistics", page_icon="📈")
 
 st.markdown("# Language Statistics")
+st.write("""\
+The table below shows the per-language statistics of the MMS corpus.  
+You can use the **'Add filters'** button to filter the table by any of the columns.  
+
+Column descriptions:
+- **Language**: Language name,
+- **Datasets**: Number of datasets in the MMS corpus for the given language,
+- **News**: Number of datasets from news domain,
+- **Reviews**: Number of datasets from reviews domain,
+- **Social media**: Number of datasets from social media domain,
+- **Other**: Number of datasets from other domains,
+- **Negative**: Number of examples with negative sentiment,
+- **Neutral**: Number of examples with neutral sentiment,
+- **Positive**: Number of examples with positive sentiment,
+- **Words**: The average number of words in a single example,
+- **Characters**: The average number of characters in a single example,""")
 
 df = get_language_stats_df()