Rename to optional to unless_blank

optional may be confusing with the optional method

lib/simple_form/wrappers/many.rb

@@ -50,7 +50,7 @@ module SimpleForm
 
       def wrap(input, options, content)
         return content if options[namespace] == false
-        return if defaults[:optional] && content.empty?
+        return if defaults[:unless_blank] && content.empty?
 
         tag = (namespace && options[:"#{namespace}_tag"]) || @defaults[:tag]
         return content unless tag

test/support/misc_helpers.rb

@@ -78,7 +78,7 @@ module MiscHelpers
 
   def custom_wrapper_with_optional_div_and_override
     SimpleForm.build tag: :section, class: "custom_wrapper" do |b|
-      b.wrapper tag: :div, class: 'no_output_wrapper', optional: true do |ba|
+      b.wrapper tag: :div, class: 'no_output_wrapper', unless_blank: true do |ba|
         ba.optional :hint, wrap_with: { tag: :p, class: 'omg_hint' }
       end
     end