feat(view): Floating nvim tree window #1377 (#1462)

* Simple mock-up of floating nvim-tree window

* Passing whole table to nvim_open_win()

* Run update-help.sh

* Use vim.api alias

* Add comment to float options

* Added `anchor` to float options

* Enabling float window enforces `actions.open_file.quit_on_open`

* Added documentation

* add view.float.open_win_config, skipping validation

* Made nvim-tree window closes when float is enabled

* Close nvim-tree window when out of focus

* Update help

Co-authored-by: Krzysztof Cieśla <krzysztof.marcin.ciesla@cern.ch>
Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/view.lua

@@ -134,8 +134,12 @@ local function set_window_options_and_buffer()
 end
 
 local function open_window()
-  a.nvim_command "vsp"
-  M.reposition_window()
+  if M.View.float.enable then
+    a.nvim_open_win(0, true, M.View.float.open_win_config)
+  else
+    a.nvim_command "vsp"
+    M.reposition_window()
+  end
   setup_tabpage(a.nvim_get_current_tabpage())
   set_window_options_and_buffer()
 end
@@ -431,6 +435,7 @@ function M.setup(opts)
   M.View.winopts.number = options.number
   M.View.winopts.relativenumber = options.relativenumber
   M.View.winopts.signcolumn = options.signcolumn
+  M.View.float = options.float
   M.on_attach = opts.on_attach
 end