TRG-668: Resolve Rubocop violations.

Not entirely sure I think all of Rubocop's corrections make the code more readable, but this is what it wants in order to pass its checks.

govuk_tech_docs.gemspec

@@ -37,6 +37,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "autoprefixer-rails", "~> 10.2"
   spec.add_dependency "chronic", "~> 0.10.2"
+  spec.add_dependency "haml", "< 6.0.0"
   spec.add_dependency "middleman", "~> 4.0"
   spec.add_dependency "middleman-autoprefixer", "~> 2.10.0"
   spec.add_dependency "middleman-compass", ">= 4.0.0"
@@ -47,7 +48,6 @@ Gem::Specification.new do |spec|
   spec.add_dependency "nokogiri"
   spec.add_dependency "openapi3_parser", "~> 0.9.0"
   spec.add_dependency "redcarpet", "~> 3.5.1"
-  spec.add_dependency "haml", "< 6.0.0"
 
   spec.add_development_dependency "byebug"
   spec.add_development_dependency "capybara", "~> 3.32"

lib/govuk_tech_docs/path_helpers.rb

@@ -1,7 +1,6 @@
 module GovukTechDocs
   module PathHelpers
-
-    require 'uri'
+    require "uri"
 
     # Some useful notes from https://www.rubydoc.info/github/middleman/middleman/Middleman/Sitemap/Resource#url-instance_method :
     # 'resource.path' is "The source path of this resource (relative to the source directory, without template extensions)."
@@ -18,24 +17,14 @@ module PathHelpers
     # @param [Object] current_page
     def get_path_to_resource(config, resource, current_page)
       if resource.instance_of?(Middleman::Sitemap::Resource)
-        if config[:relative_links]
-          resolved_path = get_resource_path_relative_to_current_page(config, current_page.path, resource.path)
-        else
-          resolved_path = resource.url
-        end
+        config[:relative_links] ? get_resource_path_relative_to_current_page(config, current_page.path, resource.path) : resource.url
+      elsif external_url?(resource)
+        resource
+      elsif config[:relative_links]
+        get_resource_path_relative_to_current_page(config, current_page.path, resource)
       else
-        if external_url?(resource)
-          resolved_path = resource
-        else
-          if config[:relative_links]
-            resolved_path = get_resource_path_relative_to_current_page(config, current_page.path, resource)
-          else
-            resolved_path = resource
-          end
-        end
+        resource
       end
-
-      resolved_path
     end
 
     def path_to_site_root(config, page_path)
@@ -50,7 +39,7 @@ def path_to_site_root(config, page_path)
       path_to_site_root
     end
 
-    private
+  private
 
     # Calculates the path to the sought resource, relative to the current page.
     # @param [Object] config Middleman config.

spec/govuk_tech_docs/path_helpers_spec.rb

@@ -65,7 +65,7 @@ def create_resource_double(**kwargs)
         "https://www.example.com/some-page.html", # With scheme included.
         "www.example.com/some-page.html", # With scheme omitted.
       ]
-      external_urls.each { | external_url |
+      external_urls.each do |external_url|
         current_page_path = "/documentation/introduction/section-one/index.html"
 
         it "when the site is configured to generate absolute links" do
@@ -87,7 +87,7 @@ def create_resource_double(**kwargs)
 
           expect(resource_path).to eql(external_url)
         end
-      }
+      end
     end
   end