add exhibition to sort by_material

plugins/cia-endpoints/cia-end-points.php

     
     $material_sorts = ['by_material'];
     $by_material_types = [
-        'artist', 'guide', 'short',
-        'object', 'publication', 'technique'
+        'artist', 'exhibition', 'short', 'technique', 'guide',  'object', 'publication'
     ];
     _make_sorts($by_material_types, $material_sorts);
     

plugins/cia-endpoints/includes/formats.php

     $filtered[hero] = get_post_meta( $item->ID, 'hero_header', true );
 
     // Materials + type endpoints
-    $posts_with_type = ['artist', 'exhibition', 'event', 'short', 'guide', 'object', 'publication', 'technique' ];
+    $posts_with_type = ['artist', 'exhibition', 'event', 'short', 'technique', 'guide', 'object', 'publication' ];
     if( in_array($item->post_type, $posts_with_type) ) {
         $filtered[materials] = make_taxonomy_endpoint_for(get_the_terms( $item, 'material'));
         $filtered[subtypes] = make_taxonomy_endpoint_for(get_the_terms( $item, $item->post_type . '_type' ));