feat: More auto-unfold options

Option to auto unfold when there is only N root nodes in outline.

Defaults to 1, meaning if there is only one 'root' parent, it should
always be unfolded.

This is useful if the entire file is a single function or a single
'return'.

The old auto_unfold_hover option **still works as expected**.

lua/outline/config.lua

@@ -60,7 +60,11 @@ M.defaults = {
   },
   symbol_folding = {
     autofold_depth = nil,
-    auto_unfold_hover = true,
+    auto_unfold_nodes = {
+      hovered = true,
+      ---@type boolean|integer
+      only = true,
+    },
     markers = { '', '' },
   },
   keymaps = {
@@ -306,6 +310,16 @@ function M.resolve_config()
   end
   ----- SYMBOLS FILTER -----
   M.resolve_filter_config()
+  ----- AUTO UNFOLD -----
+  local au = M.o.symbol_folding.auto_unfold_nodes
+  if M.o.symbol_folding.auto_unfold_hover == nil then
+    if au.hovered ~= nil then
+      M.o.symbol_folding.auto_unfold_hover = au.hovered
+    end
+  end
+  if type(au.only) ~= 'number' then
+    au.only = (au.only and 1) or 0
+  end
 end
 
 ---Ensure l is either table, false, or nil. If not, print warning using given

lua/outline/folding.lua

@@ -18,9 +18,14 @@ end
 
 ---@param node outline.SymbolNode|outline.FlatSymbolNode
 function M.is_folded(node)
+  local hover = cfg.o.symbol_folding.auto_unfold_hover
+  local only = cfg.o.symbol_folding.auto_unfold_nodes.only
+
   if node.folded ~= nil then
     return node.folded
-  elseif node.hovered and cfg.o.symbol_folding.auto_unfold_hover then
+  elseif node.parent.is_root and node.parent.child_count <= only then
+    return false
+  elseif node.hovered and hover then
     return false
   else
     return get_default_folded(node.depth)

lua/outline/parser.lua

@@ -79,7 +79,7 @@ end
 function M.parse(response, bufnr)
   local sorted = lsp_utils.sort_symbols(response)
 
-  return parse_result(sorted, nil, nil, nil, bufnr)
+  return parse_result(sorted, nil, nil, { is_root = true, child_count = #sorted }, bufnr)
 end
 
 ---Iterator that traverses the tree parent first before children, returning each node.

lua/outline/types/outline.lua

@@ -38,6 +38,7 @@
 ---@field hierarchy boolean
 ---@field children? outline.SymbolNode[]
 ---@field traversal_child integer Should NOT be modified during iteration using parser.preorder_iter
+---@field is_root boolean?
 
 ---@class outline.FlatSymbolNode
 ---@field name string
@@ -55,6 +56,7 @@
 ---@field hierarchy boolean
 ---@field children? outline.FlatSymbolNode[]
 ---@field traversal_child integer
+---@field is_root boolean?
 ---@field line_in_outline integer
 ---@field prefix_length integer
 ---@field hovered boolean