fix(docs)!: Use the new attached_to_untracked setting

Author: hankertrix

README.md

@@ -74,7 +74,7 @@ require('gitsigns').setup {
     follow_files = true
   },
   auto_attach = true,
-  attach_to_untracked = true,
+  attach_to_untracked = false,
   current_line_blame = false, -- Toggle with `:Gitsigns toggle_current_line_blame`
   current_line_blame_opts = {
     virt_text = true,

doc/gitsigns.txt

@@ -50,7 +50,7 @@ of the default settings:
         follow_files = true
       },
       auto_attach = true,
-      attach_to_untracked = true,
+      attach_to_untracked = false,
       current_line_blame = false, -- Toggle with `:Gitsigns toggle_current_line_blame`
       current_line_blame_opts = {
         virt_text = true,