Function: combined_editor

--Usage--
> forward_editor(field: some_text_value)
> combined_editor(field1: some_text_value, field2: some_text_value, ..., separator1: some_string, ...)

Use one text field to edit one or more others.

This function must be used in the @script@ of a [[type:field#text|text field]].
This field will then contain the combined values of the given fields, separated by the separators in @<sep>@ tags.
When the field changes the underlying values are updated and vice versa.

Note: @forward_editor@ and @combined_editor@ are the same function.

--Parameters--
! Parameter	Type				Default	Description
| @field@	[[type:value#text|text value]]	 	Text value to edit
| @field1@	[[type:value#text|text value]]	 	Another text value to edit
| @field2@	[[type:value#text|text value]]	 	''etc.''
| @separator@	[[type:string]]			 	Separator between field 1 and 2
| @separator1@	[[type:string]]			 	Multiple separators
| @separator2@	[[type:string]]			 	Next separator, ''etc.''
| @prefix@	[[type:string]]		''optional''	Prefix before the combined editor; like a separator between the start and the first field.
| @suffix@	[[type:string]]		''optional''	Suffix after the combined editor; like a separator between the last field and the end.
| @hide when empty@	[[type:boolean]]	@false@	Don't include separators if the entire value is empty.
| @soft before empty@	[[type:boolean]]	@false@	Make separators 'soft' when the value following it is empty.
			 			 	Soft separators are hidden by default and shown grayed when the field is selected.

--Examples--
>card field:
>	...
>	script:
>>		combined_editor(
>>			field1: card.first_part
>>			separator: " - "
>>			field2: card.second_part
>>		)

Forwarding just one field should be used in cases when two fields share a value, or when sometimes multiple fields are combined.
For example the Magic uses:
>> if set.include_automatic_card_numbers then
>>   combined_editor(field1:    card.copyright,
>>                   separator: "/",
>>                   field2:    card.card_number)
>> else
>>   forward_editor(field: card.copyright)
