fix: preserve folding when moving subtree

To be consistent with promotion and demotion commands, we preserve the
folding state also when moving a subtree.

lua/orgmode/org/mappings.lua

@@ -763,9 +763,13 @@ function OrgMappings:move_subtree_up()
   end
   local range = item:get_range()
   local target_line = prev_headline:get_range().start_line - 1
+  local foldclosed = vim.fn.foldclosed('.')
   vim.cmd(string.format(':%d,%dmove %d', range.start_line, range.end_line, target_line))
   local pos = vim.fn.getcurpos()
-  vim.fn.cursor(prev_headline:get_range().start_line, pos[2])
+  vim.fn.cursor(target_line + 1, pos[2])
+  if foldclosed > -1 and vim.fn.foldclosed('.') == -1 then
+    vim.cmd([[norm!zc]])
+  end
 end
 
 function OrgMappings:move_subtree_down()
@@ -776,9 +780,13 @@ function OrgMappings:move_subtree_down()
   end
   local range = item:get_range()
   local target_line = next_headline:get_range().end_line
+  local foldclosed = vim.fn.foldclosed('.')
   vim.cmd(string.format(':%d,%dmove %d', range.start_line, range.end_line, target_line))
   local pos = vim.fn.getcurpos()
   vim.fn.cursor(target_line + range.start_line - range.end_line, pos[2])
+  if foldclosed > -1 and vim.fn.foldclosed('.') == -1 then
+    vim.cmd([[norm!zc]])
+  end
 end
 
 function OrgMappings:show_help(type)