WooCommerce Product Search 5.4.0

* WooCommerce 4.0 compatible.
* WordPress 5.5 (alpha) compatibility tested.
* Updated minimum PHP 7.0 requirement.
* Added the option to sort results by popularity in the live Product Search Field.
* Added the option to sort results by rating in the live Product Search Field.
* Added the woocommerce_search_products_post_statuses filter to the extended product data store and using lookup table.
* Added support for WooCommerce REST API product search via the search engine.
* Added the WPS_EXT_REST constant that allows to override the REST API product search.
* Added generator meta tag for markup produced by our search engine.
* Added the woocommerce_product_search_process_query_product_taxonomies filter.
* Added support for filtering on brand product archives related to the WooCommerce Brands extension.
* Added support for keyword searches by brand related to the WooCommerce Brands extension (requires index rebuilding on existing datasets for search engine to produce keyword matches based on brand).
* Added the woocommerce_product_search_compat_woocommerce_brands_index filter.
* Added support for filtering on vendor product archives related to the WooCommerce Product Vendors extension.
* Added support for keyword searches by vendor related to the WooCommerce Product Vendors extension (requires index rebuilding on existing datasets for search engine to produce keyword matches based on vendor).
* Added the woocommerce_product_search_compat_woocommerce_product_vendors_index filter.
* Fixed an issue with the option to include empty terms having no effect (hide empty terms disabled on product categories and attributes).
* Fixed filter reset not appearing when on sale filter is active.
* Fixed an issue when filtering by products on sale and by price with no eligible products would still produce results.
* Fixed a PHP Notice when price filter without slider was used.
* Fixed price filters without slider would not reset input fields.
* Fixed price filter input fields would not trigger after clearing if previous value (before clearing) was input again.
* Improved price filter performance using WC lookup table.
* Added multi-currency WPML compatibility for price filtering (Note on 2.20.0).
* Added better consistency to price filtering with respect to the standard price filter (Note on 2.20.0).
* Noted that the current status of WC 4.0.0 & WooCommerce Multilingual 4.7.9 which do not support correct price filtering for manually set currency prices, adopted measures to remove WC_Query's posts_clauses filter during handling for consistency.
* Updated filter CSS against undesired anchor styling (text-decoration).
* Added the Product Filter – Rating widget.
* Added the [woocommerce_product_filter_rating] shortcode.
* Added the API function woocommerce_product_search_filter_rating() for use in templates etc.
* Updated some outdated links to documentation.

* WooCommerce 3.8 compatibility re-tested.
* Added the new live filter for products on sale.
* Added the Product Filter – Sale widget.
* Added the [woocommerce_product_filter_sale] shortcode.
* Added the API function woocommerce_product_search_filter_sale() for use in templates etc.
* Updated all translations.
* Fixed issues in the Indonesian translation (HTML entities and formatting).
* Fixed the assistant taking inactive widgets into account.

* Terms offered in taxonomy filters are now restricted to context on search results.
* Fixed usage of undefined variable to obtain heading_id in search filter.
* Improved how search is handled for search results pages with the Product Filter – Search, allows to narrow down results with the filter.
* Fixed uninitialized containers array in price filter.
* Fixed PHP_INT_MAX used for maximum price instead of empty maximum value in price filter, would display the odd PHP_INT_MAX when products without prices were displayed only.
* Guarded against fatal errors produced if the WC_Product_Data_Store_CPT class is missing due to messed up loading we cannot control.
* Added Jetpack synergy improvement to have our search engine take over product searches and let Jetpack still handle other search queries.
* Added the woocommerce_product_search_jetpack_search_should_handle_query filter that allows to modify our override.
* WooCommerce 3.8 compatibility tested based on current WooCommerce 3.8.0-beta.1