MDL-47797 question preview: show more technical info

It is helpful for developers creating question types (at least) to be
able to see this.

lang/en/question.php

@@ -426,8 +426,10 @@ $string['technicalinfo_help'] = 'This technical information is probably only use
 $string['technicalinfominfraction'] = 'Minimum fraction: {$a}';
 $string['technicalinfomaxfraction'] = 'Maximum fraction: {$a}';
 $string['technicalinfoquestionsummary'] = 'Question summary: {$a}';
+$string['technicalinforesponsesummary'] = 'Response summary: {$a}';
 $string['technicalinforightsummary'] = 'Right answer summary: {$a}';
 $string['technicalinfostate'] = 'Question state: {$a}';
+$string['technicalinfovariant'] = 'Question variant: {$a}';
 $string['unknownbehaviour'] = 'Unknown behaviour: {$a}.';
 $string['unknownorunhandledtype'] = 'Unknown or unhandled question type: {$a}';
 $string['unknownquestion'] = 'Unknown question: {$a}.';

question/preview.php

@@ -227,8 +227,10 @@ $technical[] = get_string('behaviourbeingused', 'question',
         question_engine::get_behaviour_name($qa->get_behaviour_name()));
 $technical[] = get_string('technicalinfominfraction',     'question', $qa->get_min_fraction());
 $technical[] = get_string('technicalinfomaxfraction',     'question', $qa->get_max_fraction());
+$technical[] = get_string('technicalinfovariant',         'question', $qa->get_variant());
 $technical[] = get_string('technicalinfoquestionsummary', 'question', s($qa->get_question_summary()));
 $technical[] = get_string('technicalinforightsummary',    'question', s($qa->get_right_answer_summary()));
+$technical[] = get_string('technicalinforesponsesummary', 'question', s($qa->get_response_summary()));
 $technical[] = get_string('technicalinfostate',           'question', '' . $qa->get_state());
 
 // Start output.