misc: remove extra_data function

doc/function/extra_data.txt

@@ -1,27 +0,0 @@
-Function: extra_data
-
-DOC_MSE_VERSION: since 2.2.0
-
---Usage--
-> extra_data("field_name")
-
-Access the value of extra card fields.
-
-Due to lazy initialization of stylesheet specific Extra Card Fields they are not exposed directly from the card using `card.field_name` syntax.
-As a workaround this function returns the Value of the specified field name for the active card using an access pattern that supports late resolution of the value for the active stylesheet.
-
---Parameters--
-! Parameter	Type	Description
-| @input@	[[type:string]]	Field name, with or without underscores.
-
---Examples--
-
->extra card field:
->	...
->	name: my first extra field
->
->extra card field:
->	...
->	name: my second extra field
->	script:
->>		space_to_comma(extra_data("my first extra field")) + "!"

doc/function/index.txt

@@ -65,8 +65,7 @@ These functions are built into the program, other [[type:function]]s can be defi
 | [[fun:english_plural|english_singular]]		Find the singular of a word, @"cards" -> "card"@.
 | [[fun:process_english_hints]]				Process the hints left by english_ functions in a keyword's reminder text.
 	
-! Fields and values			<<<
-| [[fun:extra_data]]	Access the value of extra card fields.
+! Fields and values			<<<
 | [[fun:combined_editor|forward_editor]]	Use one field to edit another.
 | [[fun:combined_editor]]		Use one field to edit multiple others.
 | [[fun:primary_choice]]		Return the top level choice chosen from a choice field.

src/script/functions/editor.cpp

@@ -382,26 +382,6 @@ SCRIPT_FUNCTION(count_chosen) {
       SCRIPT_RETURN(count);
     }
   }
-}
-
-// ----------------------------------------------------------------------------- : Extra Card Fields
-
-SCRIPT_FUNCTION(extra_data) {
-  SCRIPT_PARAM_C(String, input);
-  SCRIPT_PARAM_C(CardP, card);
-  SCRIPT_PARAM_C(StyleSheetP, stylesheet);
-
-  // Transform input to standard field name syntax.
-  // Other functions are doing lookups for ValuePs, which I assume is doing some of this automatically.
-  String canonical_field_name = canonical_name_form(input);
-
-  FOR_EACH(valueP, card->extraDataFor(*stylesheet)) {
-    if (valueP->fieldP->name == canonical_field_name) {
-      SCRIPT_RETURN(valueP);
-    }
-  }
-
-  return delay_error(ScriptErrorNoMember("extra_data()", input));
 }
 
 // ----------------------------------------------------------------------------- : Init
@@ -415,6 +395,5 @@ void init_script_editor_functions(Context& ctx) {
   ctx.setVariable(_("require_choice"),           script_require_choice);
   ctx.setVariable(_("exclusive_choice"),         script_exclusive_choice);
   ctx.setVariable(_("require_exclusive_choice"), script_require_exclusive_choice);
-  ctx.setVariable(_("remove_choice"),            script_remove_choice);
-  ctx.setVariable(_("extra_data"),               script_extra_data);
+  ctx.setVariable(_("remove_choice"),            script_remove_choice);
 }