Render breadcrumb links for module's parents

This converts the name displayed at the top of each module's page into
breadcrumb links.  Each part of the name now links to the corresponding
parent module's page.

Closes #212.

Author: jonathanhefner

lib/rdoc/generator/template/rails/class.rhtml

@@ -21,7 +21,7 @@
     <main id="content">
         <div class="content__full-name">
           <span class="qualifier"><%= klass.type %></span>
-          <%= full_name klass %>
+          <%= module_breadcrumbs klass %>
           <% if !klass.module? && superclass = klass.superclass %>
             <span class="qualifier">&lt;</span>
             <%= superclass.is_a?(String) ? full_name(superclass) : link_to(superclass) %>

lib/rdoc/generator/template/rails/resources/css/main.css

@@ -55,6 +55,9 @@ a {
 a:has(> code:only-child) {
   text-decoration: none;
 }
+code a {
+  text-decoration: none;
+}
 
 /* TODO: Remove this hack when Firefox supports `:has()` */
 a code {

lib/sdoc/helpers.rb

@@ -116,6 +116,17 @@ def more_less_ul(items, limit)
     end
   end
 
+  def module_breadcrumbs(rdoc_module)
+    crumbs = [h(rdoc_module.name)]
+
+    rdoc_module.each_parent do |parent|
+      break if parent.is_a?(RDoc::TopLevel)
+      crumbs.unshift(link_to(h(parent.name), parent))
+    end
+
+    "<code>#{crumbs.join("::<wbr>")}</code>"
+  end
+
   def method_signature(rdoc_method)
     if rdoc_method.call_seq
       rdoc_method.call_seq.split(/\n+/).map do |line|

spec/helpers_spec.rb

@@ -502,6 +502,27 @@ def ul(items)
     end
   end
 
+  describe "#module_breadcrumbs" do
+    it "renders links for each of the module's parents" do
+      top_level = rdoc_top_level_for <<~RUBY
+        module Foo; module Bar; module Qux; end; end; end
+      RUBY
+
+      foo = top_level.find_module_named("Foo")
+      bar = top_level.find_module_named("Foo::Bar")
+      qux = top_level.find_module_named("Foo::Bar::Qux")
+
+      _(@helpers.module_breadcrumbs(foo)).
+        must_equal "<code>Foo</code>"
+
+      _(@helpers.module_breadcrumbs(bar)).
+        must_equal "<code>#{@helpers.link_to "Foo", foo}::<wbr>Bar</code>"
+
+      _(@helpers.module_breadcrumbs(qux)).
+        must_equal "<code>#{@helpers.link_to "Foo", foo}::<wbr>#{@helpers.link_to "Bar", bar}::<wbr>Qux</code>"
+    end
+  end
+
   describe "#method_signature" do
     it "returns the method signature wrapped in <code>" do
       method = rdoc_top_level_for(<<~RUBY).find_module_named("Foo").find_method("bar", false)