Remove .gitignore only managing Emacs editor's backup files.

You can manage such specific settings by core.excludesFile in the user’s
~/.gitconfig according to the following Git document.

https://git-scm.com/docs/gitignore

> Patterns which a user wants Git to ignore in all situations (e.g., backup or
> temporary files generated by the user’s editor of choice) generally go into
> a file specified by core.excludesFile in the user’s ~/.gitconfig. Its
> default value is $XDG_CONFIG_HOME/git/ignore. If $XDG_CONFIG_HOME is either
> not set or empty, $HOME/.config/git/ignore is used instead.

You can refer to .gitignore settings for editors on the following repository
including Emacs and Vim settings.

https://github.com/github/gitignore/tree/main/Global

* https://github.com/github/gitignore/blob/main/Global/Emacs.gitignore
* https://github.com/github/gitignore/blob/main/Global/Vim.gitignore

.gitignore

@@ -1 +0,0 @@
-*~