Better clarity on case-when indentation

This replaces PR rubocop#422, and maintains a minimum of overall new lines

Author: NewAlexandria

README.md

@@ -327,8 +327,12 @@ Translations of the guide are available in the following languages:
         puts 'Not again!'
       when song.duration > 120
         puts 'Too long!'
-      when Time.now.hour > 21
-        puts "It's too late"
+      when :minus_op, :minus_minus_op
+        stack.pop - stack.pop
+      when MyModule::SomeDomain::BETA_USERS, MyModule::SomeDomain::INTERNAL_RELEASE
+        stack.pop + stack.pop
+      when :int_literal, :some_complicate_explicit_name, :contains_musicians_with_arms, :str_interpolated
+        token.value
       else
         song.play
     end
@@ -341,11 +345,26 @@ Translations of the guide are available in the following languages:
       puts 'Too long!'
     when Time.now.hour > 21
       puts "It's too late"
+    when :minus_op, :minus_minus_op
+      stack.pop - stack.pop
+    when MyModule::SomeDomain::BETA_USERS,
+         MyModule::SomeDomain::INTERNAL_RELEASE
+      stack.pop + stack.pop
+   	when :int_literal,
+	        :some_complicate_explicit_name,
+	        :contains_musicians_with_arms,
+	        :str_interpolated
+      token.value
     else
       song.play
     end
     ```
 
+    Put multiple when conditions on separate lines,
+    particularly where the conditions form long, complicated lines.
+    The 'bad' example also has the issue of causing the entire when line to
+    diff when only one of the conditions is changed or updated.
+
   * <a name="indent-conditional-assignment"></a>
     When assigning the result of a conditional expression to a variable,
     preserve the usual alignment of its branches.