feat: add renderer.highlight_hidden, renderer.icons.show.hidden and renderer.icons.hidden_placement for dotfile icons/highlights (#2840)

* feat(hidden_decorator): Allow hidden (dotfiles) to be highlighted, both icon and name (this not related to git highlights).

Better defaults

squashed

docs(hidden)

docs(hidden)

docs(hidden)

* fix(typo): small typo on hl groups

* feat(hidden_dotfile_highlight): make a file that has a dotfile parent be also a dotfile

* docs: update docs on hidden highlight

---------

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/explorer/node.lua

@@ -128,6 +128,19 @@ function M.is_git_ignored(node)
   return node and node.git_status ~= nil and node.git_status.file == "!!"
 end
 
+---@param node Node
+---@return boolean
+function M.is_dotfile(node)
+  if node == nil then
+    return false
+  end
+  if node.is_dot or (node.name and (node.name:sub(1, 1) == ".")) or M.is_dotfile(node.parent) then
+    node.is_dot = true
+    return true
+  end
+  return false
+end
+
 ---@param node Node
 function M.node_destroy(node)
   if not node then