fix(facet): document selected_facet alias

Author: lovasoa

examples/official-site/sqlpage/migrations/77_facet.sql

@@ -32,7 +32,7 @@ INSERT INTO parameter(component, name, description, type, top_level, optional) S
     -- Top-level parameters
     ('description','The facet category label.','TEXT',TRUE,TRUE),
     ('dropdown_title','Text shown on the compact-mode dropdown button when no facet is selected. Defaults to `Choose facet`.','TEXT',TRUE,TRUE),
-    ('selected_facet','Text shown on the compact-mode dropdown button when facet has been selected. Use it to show the active facet.','TEXT',TRUE,TRUE),
+    ('selected_facet','An alias for `dropdown_title`.','TEXT',TRUE,TRUE),
     ('compact','Displays the facets in a dropdown instead of links.','BOOLEAN',TRUE,TRUE),
     ('center','Whether to center the facet selector','BOOLEAN',TRUE,TRUE),
     ('all_link','URL that clears the filter. If omitted, no All link is displayed.','URL',TRUE,TRUE),

sqlpage/templates/facet.handlebars

@@ -8,7 +8,7 @@
     {{#if description}}<span class="fw-bold">{{description}}:</span>{{/if}}
     <div class="dropdown d-inline-block">
         <button class="btn btn-primary dropdown-toggle" type="button" data-bs-toggle="dropdown" aria-expanded="false">
-            {{#if selected_facet}}{{selected_facet}}{{else}}{{(default dropdown_title (default description "Choose facet"))}}{{/if}}
+            {{default selected_facet (default dropdown_title (default description "Choose facet"))}}
         </button>
         <div class="dropdown-menu">
             {{#if all_link}}