search: refactor scan_query callers to use split_query.

Refactor to use split_query instead of scan_query to split a query on
spaces. Preparation for refactoring scan_query into something smarter.

app/logical/alias_and_implication_importer.rb

@@ -88,8 +88,8 @@ class AliasAndImplicationImporter
         all
 
       when :mass_update
-        all += PostQueryBuilder.scan_query(token[1])
-        all += PostQueryBuilder.scan_query(token[2])
+        all += PostQueryBuilder.split_query(token[1])
+        all += PostQueryBuilder.split_query(token[2])
         all
 
       when :change_category

app/logical/post_query_builder.rb

@@ -760,6 +760,10 @@ class PostQueryBuilder
         list
       end
 
+      def split_query(query)
+        scan_query(query)
+      end
+
       def normalize_query(query, normalize_aliases: true, sort: true)
         tags = scan_query(query.to_s)
         tags = tags.map { |t| Tag.normalize_name(t) }

app/logical/post_sets/post.rb

@@ -4,7 +4,7 @@ module PostSets
     attr_reader :tag_array, :page, :raw, :random, :post_count, :format
 
     def initialize(tags, page = 1, per_page = nil, raw: false, random: false, format: "html")
-      @tag_array = PostQueryBuilder.scan_query(tags)
+      @tag_array = PostQueryBuilder.split_query(tags)
       @page = page
       @per_page = per_page
       @raw = raw.to_s.truthy?