List deprecated option aliases in the docs

doc/manual/generate-options.jq

@@ -1,11 +1,16 @@
 . | to_entries | sort_by(.key) | map(
   "  - `" + .key + "`  \n\n"
   + (.value.description | split("\n") | map("    " + . + "\n") | join("")) + "\n\n"
-  + "    **Default**: " + (
+  + "    **Default:** " + (
       if .value.value == "" or .value.value == []
       then "*empty*"
       elif (.value.value | type) == "array"
       then "`" + (.value.value | join(" ")) + "`"
-      else "`" + (.value.value | tostring) + "`" end)
+      else "`" + (.value.value | tostring) + "`"
+      end)
   + "\n\n"
+  + (if (.value.aliases | length) > 0
+     then "    **Deprecated alias:** " + (.value.aliases | map("`" + . + "`") | join(", ")) + "\n\n"
+     else ""
+     end)
 ) | join("")

src/libutil/config.cc

@@ -139,6 +139,7 @@ nlohmann::json Config::toJSON()
         if (!s.second.isAlias) {
             auto obj = nlohmann::json::object();
             obj.emplace("description", s.second.setting->description);
+            obj.emplace("aliases", s.second.setting->aliases);
             obj.emplace("value", s.second.setting->toJSON());
             res.emplace(s.first, obj);
         }