Lua: fix generated docs.

Update and fix docs for `pandoc.types.Version` and `pandoc.utils.type`.

tools/update-lua-module-docs.lua

@@ -54,6 +54,7 @@ local known_types = {
   SimpleTable = 'type-simpletable',
   Table = 'type-table',
   WriterOptions = 'type-writeroptions',
+  Version = 'type-version',
 }
 
 local function render_typespec (typespec)
@@ -256,21 +257,6 @@ local handled_modules = {
   layout = true
 }
 
-local modules = {
-  -- 'cli',
-  -- 'utils',
-  -- 'mediabag',
-  -- 'format',
-  -- 'path',
-  -- 'structure',
-  -- 'system',
-  -- 'layout',
-  -- 'scaffolding',
-  -- 'template',
-  -- 'types',
-  'zip',
-}
-
 -- Generate docs for the given module
 if arg and arg[1] then
   local module_name = arg[1]