templates/table.html: use ['count'] for the count-all click handler

Warehouse overrides datasette's table.html via --template-dir, so the
upstream fix on duckdb-deploy doesn't reach the rendered page — the
warehouse copy still had data['rows'][0]['count(*)'] which is wrong
on DuckDB (returns null since the column is named 'count_star()').

Match the upstream fix here. (The SQLite track is unaffected because
SQLite returns 'count(*)' as the column name; the upstream change
aliases to 'count' which is what this JS now reads.)

Author: fgregg

templates/table.html

@@ -211,7 +211,10 @@ <h3>Download this data</h3>
                     console.log('throw error');
                     throw new Error(data.title || data.error);
                 }
-                const count = data['rows'][0]['count(*)'];
+                // SQL aliases the column to `count` (datasette views/table.py)
+                // so this works on any backend — SQLite would otherwise return
+                // key "count(*)", DuckDB "count_star()".
+                const count = data['rows'][0]['count'];
                 const formattedCount = count.toLocaleString();
                 span.closest('h3').textContent = formattedCount + ' rows';
             } catch (error) {