refactor(defaults): edit global cwd on "1-" #41254

Problem:
`1-` does nothing from a directory buffer, because we are already in the
buffer-local CWD. It's also unintuitive that this mapping behaves
differently based on the resolved CWD.

Solution:
Have `1-` open the global CWD.

test/functional/plugin/dir_spec.lua

@@ -433,6 +433,13 @@ describe('nvim.dir', function()
 
     assert_directory(cwd)
 
+    edit(file)
+    feed('-')
+    poke_eventloop()
+    feed('1-')
+    poke_eventloop()
+    assert_directory(cwd)
+
     edit(file)
     feed('2-')
     poke_eventloop()