feat(actions): expand all under folder (#1292)

doc/nvim-tree-lua.txt

@@ -208,6 +208,9 @@ Values may be functions. Warning: this may result in unexpected behaviour.
           global = false,
           restrict_above_cwd = false,
         },
+        expand_all = {
+          max_folder_discovery = 300,
+        },
         open_file = {
           quit_on_open = false,
           resize_window = true,
@@ -633,6 +636,11 @@ Configuration for various actions.
     Restrict changing to a directory above the global current working directory.
       Type: `boolean`, Default: `false`
 
+    *nvim-tree.actions.expand_all.max_folder_discovery*
+    Limit the number of folders being explored when expanding every folders.
+    Avoids hanging neovim when running this action on very large folders.
+      Type: `number`, Default: `300`
+
     *nvim-tree.actions.open_file.quit_on_open*
     Closes the explorer when opening a file.
     It will also disable preventing a buffer overriding the tree.
@@ -762,6 +770,8 @@ INFORMATIONS                                         *nvim-tree-info*
 - Double left click acts like <CR>
 - Double right click acts like <C-]>
 - `W` will collapse the whole tree
+- `E` will expand the whole tree. Be aware this might hang neovim for a while
+  if running on a big folder (such as home dir or root dir).
 - `S` will prompt the user to enter a path and then expands the tree to match the path
 - `.` will enter vim command mode with the file the cursor is on
 - `C-k` will toggle a popup with file infos about the file under the cursor
@@ -807,6 +817,7 @@ Defaults to:
       { key = "q",                            action = "close" },
       { key = "g?",                           action = "toggle_help" },
       { key = 'W',                            action = "collapse_all" },
+      { key = 'E',                            action = "expand_all" },
       { key = "S",                            action = "search_node" },
       { key = ".",                            action = "run_file_command" },
       { key = "<C-k>",                        action = "toggle_file_info" }