WooCommerce Product Search 5.4.0

* Considerably improves the accuracy and performance of large product set searches on the back end when enabled.
* Added options to handle JSON product searches; introduced substantial performance improvements for those.
* Added the woocommerce_product_search_ext_product_data_store filter.
* Improvement to also index products with private post status so they can be included in back end search results.
* Added the WPS_EXT_PDS constant that enables the PDS override.

* Added the Spanish translation.
* Corrected some errors in descriptions.
* Fixed an issue that made the [woocommerce_product_filter_reset] shortcode inaccessible.
* Fixed translations were not loaded in time for widgets on the back end.
* Fixed incorrect img attributes generated for product tag filter thumbnails.

* Added an interactive price slider to the price filter (supported by widget, shortcode and API function).
* Added options to display the price filter with slider and/or input fields.
* Fixed and improved overlapping request handling for live search and filter actions.
* Added filter reset widget, shortcode and API functions.
* Improved UX using page cursor progress indicator while filter requests are loading.
* Improved handling of filter requests in case of request error to bring the UI elements back to a consistent state.
* Fixed indicating the parent term for the product category filter had no effect.
* Fixed the indexer's memory limit check when the configuration option is set to unlimited or doesn't exist.
* Improved initial default work cycle so it won't exceed the idle cycle by default and also checks max_input_time.
* Added check for max_input_time during indexing.
* Added the woocommerce_product_search_indexer_limit filter.
* Added the woocommerce_product_search_indexer_check_memory_limit filter.
* Added the woocommerce_product_search_indexer_check_execution_limit filter.
* Suppressed warnings from empty indexing requests (e.g. when a product has no related tags).
* Fixed back end search to include out of stock products and those that are in draft or pending.
* Fixed an issue when "Enable AJAX add to cart buttons on archives" was disabled, clicking the button from within live results would lead to a blank page showing 0.
* Added the option to render the product category filters as select/dropdown.
* Added the option to render the product attribute filters as select/dropdown.
* Added the woocommerce_product_search_term_node_select_apply_padding filter.
* Added the woocommerce_product_search_term_node_select_padding_string filter.
* Added the woocommerce_product_search_term_node_select_padding filter.