Style fixes for Rubocop 0.42.0

- var == 0 becomes var.zero?
- when defining method_missing, also define respond_to_missing?

features/support/helpers.rb

@@ -91,7 +91,7 @@ end
 def run_jekyll(args)
   args = args.strip.split(" ") # Shellwords?
   process = run_in_shell(Paths.jekyll_bin.to_s, *args, "--trace")
-  process.exitstatus == 0
+  process.exitstatus.zero?
 end
 
 #

lib/jekyll/collection.rb

@@ -25,7 +25,7 @@ module Jekyll
 
     # Override of normal respond_to? to match method_missing's logic for
     # looking in @data.
-    def respond_to?(method, include_private = false)
+    def respond_to_missing?(method, include_private = false)
       docs.respond_to?(method.to_sym, include_private) || super
     end
 

lib/jekyll/configuration.rb

@@ -374,7 +374,7 @@ module Jekyll
 
     private
     def check_maruku(config)
-      if config.fetch("markdown", "kramdown").to_s.casecmp("maruku") == 0
+      if config.fetch("markdown", "kramdown").to_s.casecmp("maruku").zero?
         Jekyll.logger.abort_with "Error:", "You're using the 'maruku' " \
           "Markdown processor, which has been removed as of 3.0.0. " \
           "We recommend you switch to Kramdown. To do this, replace " \

lib/jekyll/document.rb

@@ -367,7 +367,7 @@ module Jekyll
     def <=>(other)
       return nil unless other.respond_to?(:data)
       cmp = data["date"] <=> other.data["date"]
-      cmp = path <=> other.path if cmp.nil? || cmp == 0
+      cmp = path <=> other.path if cmp.nil? || cmp.zero?
       cmp
     end
 

lib/jekyll/drops/document_drop.rb

@@ -25,7 +25,7 @@ module Jekyll
       def <=>(other)
         return nil unless other.is_a? DocumentDrop
         cmp = self["date"] <=> other["date"]
-        cmp = self["path"] <=> other["path"] if cmp.nil? || cmp == 0
+        cmp = self["path"] <=> other["path"] if cmp.nil? || cmp.zero?
         cmp
       end
 

lib/jekyll/liquid_renderer/table.rb

@@ -43,7 +43,7 @@ module Jekyll
       str = ""
 
       row_data.each_with_index do |cell_data, cell_index|
-        str << if cell_index == 0
+        str << if cell_index.zero?
                  cell_data.ljust(widths[cell_index], " ")
                else
                  cell_data.rjust(widths[cell_index], " ")