Add ability to mark tags as deprecated

* Deprecated tags can't be added to posts, but existing deprecated tags
  in a post won't be removed
* Only empty tags can be marked as deprecated manually
* No tags can be manually undeprecated
** These limits don't apply to admins
* Deprecating or undeprecating a tag will create a new mod action to
  prevent people from going rogue
* Added deprecate/undeprecate commands for BURs
* Deprecating a tag via BUR removes all implications to and from it as well

app/views/posts/index.html.erb

@@ -121,6 +121,10 @@
           <%= format_text(wiki_page.body) %>
           <%= render "tag_relationships/alias_and_implication_list", tag: wiki_page.tag %>
 
+          <% if wiki_page.tag&.is_deprecated? %>
+            <p class="fineprint">This tag is <%= link_to "deprecated", wiki_page_path("help:deprecation_notice") %> and can't be added to new posts.</p>
+          <% end %>
+
           <p class="mt-4">
             <%= link_to_wiki "View wiki", wiki_page.title, id: "view-wiki-link" %>
           </p>
@@ -154,6 +158,10 @@
       <p>There is no wiki page yet for the tag <%= link_to_wiki @post_set.tag.pretty_name %>. <%= link_to "Create new wiki page", new_wiki_page_path(wiki_page: { title: @post_set.tag.name }), rel: "nofollow" %>.</p>
 
       <%= render "tag_relationships/alias_and_implication_list", tag: @post_set.tag %>
+
+      <% if @post_set.tag&.is_deprecated? %>
+        <p class="fineprint">This tag is <%= link_to "deprecated", wiki_page_path("help:deprecation_notice") %> and can't be added to new posts.</p>
+      <% end %>
     <% end %>
   </div>
 

app/views/tags/_search.html.erb

@@ -2,6 +2,7 @@
   <%= f.input :name_or_alias_matches, label: "Name", input_html: { value: params[:search][:name_or_alias_matches], data: { autocomplete: "tag" } } %>
   <%= f.input :category, label: "Category", collection: TagCategory.canonical_mapping.to_a, include_blank: true,selected: params[:search][:category] %>
   <%= f.input :order, collection: [%w[Newest date], %w[Count count], %w[Name name]], include_blank: false, selected: params[:search][:order] %>
+  <%= f.input :is_deprecated, label: "Is deprecated?", collection: %w[yes no], include_blank: true, selected: params[:search][:is_deprecated] %>
   <%= f.input :hide_empty, label: "Hide empty?", collection: %w[yes no], selected: params[:search][:hide_empty] %>
   <%= f.input :has_wiki_page, label: "Has wiki?", collection: %w[yes no], include_blank: true, selected: params[:search][:has_wiki_page] %>
   <%= f.input :has_artist, label: "Has artist?", collection: %w[yes no], include_blank: true, selected: params[:search][:has_artist] %>

app/views/tags/edit.html.erb

@@ -5,10 +5,20 @@
     <%= edit_form_for(@tag) do |f| %>
       <% if policy(@tag).can_change_category? %>
         <%= f.input :category, collection: TagCategory.canonical_mapping.to_a, include_blank: false %>
-        <%= f.button :submit, "Submit" %>
       <% else %>
         <p>Create a <%= link_to "bulk update request", new_bulk_update_request_path(bulk_update_request: { script: "category #{@tag.name} -> general" }) %> to change this tag's category.</p>
       <% end %>
+
+      <% if policy(@tag).can_change_deprecated_status? %>
+        <%= f.input :is_deprecated, :collection => [["No", "false"], ["Yes", "true"]], :include_blank => false %>
+      <% else %>
+        <% if @tag.is_deprecated? %>
+        <p>Create a <%= link_to "bulk update request", new_bulk_update_request_path(bulk_update_request: { script: "deprecate #{@tag.name}" }) %> to mark this tag as not deprecated.</p>
+        <% else %>
+        <p>Create a <%= link_to "bulk update request", new_bulk_update_request_path(bulk_update_request: { script: "undeprecate #{@tag.name}" }) %> to mark this tag as deprecated.</p>
+        <% end %>
+      <% end %>
+      <%= f.button :submit, "Submit" %>
     <% end %>
   </div>
 </div>

app/views/tags/show.html.erb

@@ -8,6 +8,9 @@
     <ul>
       <li>Count: <%= @tag.post_count %></li>
       <li>Category: <%= @tag.category_name %></li>
+      <% if @tag.is_deprecated? %>
+        <li> This tag is <%= link_to "deprecated", wiki_page_path("help:deprecation_notice") %> and can't be added to new posts.</li>
+      <% end %>
     </ul>
   </div>
 </div>

app/views/wiki_pages/new.html.erb

@@ -18,6 +18,11 @@
   <% end %>
 
   <%= render "tag_relationships/alias_and_implication_list", tag: @wiki_page.tag %>
+
+  <% if @wiki_page.tag&.is_deprecated? %>
+    <p class="fineprint">This tag is <%= link_to "deprecated", wiki_page_path("help:deprecation_notice") %> and can't be added to new posts.</p>
+  <% end %>
+
   <%= render "wiki_pages/posts", wiki_page: @wiki_page %>
 <% end %>
 

app/views/wiki_pages/show.html.erb

@@ -37,6 +37,10 @@
     <% end %>
 
     <%= render "tag_relationships/alias_and_implication_list", tag: @wiki_page.tag %>
+
+    <% if @wiki_page.tag&.is_deprecated? %>
+      <p class="fineprint">This tag is <%= link_to "deprecated", wiki_page_path("help:deprecation_notice") %> and can't be added to new posts.</p>
+    <% end %>
   </div>
 
   <%= render "wiki_pages/posts", wiki_page: @wiki_page %>