chore(*.psql): consistent delimiter in file names

queries/selects/top_artists.psql

@@ -0,0 +1,13 @@
+SELECT
+  l.artist_name,
+  TO_CHAR(COUNT(l.id), 'FM999,999,999') AS total_listens
+FROM
+  optimized_listens l
+WHERE
+  EXTRACT(YEAR FROM TO_TIMESTAMP(l.listened_at)) = EXTRACT(YEAR FROM CURRENT_DATE)
+  AND l.artist_name IS NOT NULL
+GROUP BY
+  l.artist_name
+ORDER BY
+  COUNT(l.id) DESC
+LIMIT 10;