Add class level documentation for Hyrax::CatalogSearchBuilder

app/search_builders/hyrax/catalog_search_builder.rb

@@ -1,3 +1,31 @@
+##
+# The default Blacklight catalog `search_builder_class` for Hyrax.
+#
+# Use of this builder is configured in the `CatalogController` generated by
+# Hyrax's install task.
+#
+# If you plan to customize the base catalog search builder behavior (e.g. by
+# adding a mixin module provided by a blacklight extension gem), inheriting this
+#  class, customizing behavior, and reconfiguring `CatalogController` is the
+# preferred mechanism.
+#
+# @example extending and customizing SearchBuilder
+#   class MyApp::CustomCatalogSearchBuilder < Hyrax::CatalogSearchBuilder
+#     include BlacklightRangeLimit::RangeLimitBuilder
+#     # and/or other extensions
+#   end
+#
+#   class CatalogController < ApplicationController
+#     # ...
+#     configure_blacklight do |config|
+#       config.search_builder_class = MyApp::CustomCatalogSearchBuilder
+#     # ...
+#     end
+#     # ...
+#   end
+#
+# @see Blacklight::SearchBuilder
+# @see Hyrax::SearchFilters
 class Hyrax::CatalogSearchBuilder < Hyrax::SearchBuilder
   self.default_processor_chain += [
     :add_access_controls_to_solr_params,