tools: fix json doc generation

Current processList function in tools/doc/json.js does not recognise
{"type":"loose_item_start"}. Fix it.
PR-URL: #5943Fixes: #5942
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Robert Lindstädt <robert.lindstaedt@gmail.com>

Author: firedfox

tools/doc/json.js

@@ -183,7 +183,7 @@ function processList(section) {
 list.forEach(function(tok){
 vartype=tok.type;
 if(type==='space')return;
-if(type==='list_item_start'){
+if(type==='list_item_start'||type==='loose_item_start'){
 varn={};
 if(!current){
 values.push(n);