fix: ignore Nvim local config #37805

Problem:
Presumably Neovim contributors use Neovim to write the contributed code.
Chances are that they have some local Neovim-source-specific config, for
example setting the $TEST_FILE and 'makeprg' for files in test/.

Solution:
Ignore it.

.gitignore

@@ -8,6 +8,9 @@ compile_commands.json
 /.vs/
 /.vscode/
 /.idea/
+.nvimrc
+.exrc
+.nvim.lua
 
 # Build/deps dir
 /.zig-cache/