Fix fmt error.

lib/jekyll/url.rb

@@ -105,7 +105,8 @@ module Jekyll
         winner = pool.find { |key| @placeholders.key?(key) }
         if winner.nil?
           raise NoMethodError,
-            "The URL template doesn't have #{pool.join(" or ")} keys. Check your permalink template!"
+            "The URL template doesn't have #{pool.join(" or ")} keys. "\
+              "Check your permalink template!"
         end
 
         value = @placeholders[winner]

test/test_url.rb

@@ -74,7 +74,7 @@ class TestURL < JekyllUnitTest
     should "check for key without trailing underscore" do
       _, matching_doc = fixture_document("_methods/configuration.md")
       assert_equal "/methods/2016-11-10_configuration", URL.new(
-        :template => "/methods/:year-:month-:day_:title",
+        :template     => "/methods/:year-:month-:day_:title",
         :placeholders => matching_doc.url_placeholders
       ).to_s
     end