UX: Various improvements to welcome topic CTA (#21010)

- Update welcome topic copy
- Edit the welcome topic automatically when the title or description changes
- Remove “Create your Welcome Topic” banner/CTA
- Add "edit welcome topic" user tip

lib/post_revisor.rb

@@ -694,7 +694,6 @@ class PostRevisor
 
     update_topic_excerpt
     update_category_description
-    hide_welcome_topic_banner
   end
 
   def update_topic_excerpt
@@ -716,15 +715,6 @@ class PostRevisor
     end
   end
 
-  def hide_welcome_topic_banner
-    return unless guardian.is_admin?
-    return unless @topic.id == SiteSetting.welcome_topic_id
-    return unless Discourse.cache.read(Site.welcome_topic_banner_cache_key(@editor.id))
-
-    Discourse.cache.write(Site.welcome_topic_banner_cache_key(@editor.id), false)
-    MessageBus.publish("/site/welcome-topic-banner", false)
-  end
-
   def advance_draft_sequence
     @post.advance_draft_sequence
   end

lib/seed_data/topics.rb

@@ -84,8 +84,14 @@ module SeedData
         if general_category = Category.find_by(id: SiteSetting.general_category_id)
           topics << {
             site_setting_name: "welcome_topic_id",
-            title: I18n.t("discourse_welcome_topic.title"),
-            raw: I18n.t("discourse_welcome_topic.body", base_path: Discourse.base_path),
+            title: I18n.t("discourse_welcome_topic.title", site_title: SiteSetting.title),
+            raw:
+              I18n.t(
+                "discourse_welcome_topic.body",
+                base_path: Discourse.base_path,
+                site_title: SiteSetting.title,
+                site_description: SiteSetting.site_description,
+              ),
             category: general_category,
             after_create: proc { |post| post.topic.update_pinned(true, true) },
           }

lib/topic_query_params.rb

@@ -18,18 +18,6 @@ module TopicQueryParams
       :no_subcategories
     ].present?
 
-    if hide_welcome_topic?
-      options[:except_topic_ids] ||= []
-      options[:except_topic_ids] << SiteSetting.welcome_topic_id
-    end
-
     options
   end
-
-  private
-
-  def hide_welcome_topic?
-    return false if !SiteSetting.bootstrap_mode_enabled
-    Site.welcome_topic_exists_and_is_not_edited?
-  end
 end