Fix test_command_error for neovim 0.12.x.

In neovim 0.12.0, the error message for an invalid cursor position changed from
"Cursor position outside buffer" to "Invalid cursor line: out of range".  Update
the test to accept both messages.

Taken from upstream commit d89b62ed622976c8d6dbc7733a99dac371b01cbf.

diff --git a/test/test_vim.py b/test/test_vim.py
index 8a76f5e..26e2fce 100644
--- a/test/test_vim.py
+++ b/test/test_vim.py
@@ -1,6 +1,7 @@
 """Tests interaction with neovim via Nvim API (with child process)."""
 
 import os
+import re
 import sys
 import tempfile
 from pathlib import Path
@@ -50,7 +51,7 @@ def test_command_output(vim: Nvim) -> None:
 def test_command_error(vim: Nvim) -> None:
     with pytest.raises(vim.error) as excinfo:
         vim.current.window.cursor = -1, -1
-    assert excinfo.value.args == ('Cursor position outside buffer',)
+    assert re.search(r"Cursor position outside buffer|Invalid cursor line", excinfo.value.args[0])
 
 
 def test_eval(vim: Nvim) -> None: