ISIS-1899: updates document.html.erb version to 1.16.2
ISIS-1899: updates document.html.erb version to 1.16.2

prior to republishing 1.16.2 docs with updated content

apache/isis,estatio/isis,incodehq/isis,incodehq/isis,estatio/isis,apache/isis,apache/isis,estatio/isis,incodehq/isis,apache/isis,incodehq/isis,apache/isis,apache/isis,estatio/isis