Fix socketed item description

[mofr]

That one (Item.DescribeProperty func 14) is incorrect, it’s
sb.Append(prop.param); and not value

Also the block.stat == null will not trigger because
block.stat = item_numsockets
But the prop item_numsockets do not have a description function so it will reach line 593 but has nothing to display.
Example
[id] => sock
[is_active] => 1
[block1_set] =>
[block1_val] =>
[block1_func] => 14
[block1_stat] => item_numsockets
[notes] => none
[affixId] => Jeweler's
[param] => 4
[min] =>
[max] =>
[value] => 0

That one is a bit tricky, it can use the param on some affixes like Jeweler that add a fix 4 sockets, while it can use the value like on Mechanist affix with a min/max, so it require a double check, if param is set use that, otherwise use value.

cc @giviz