fix: use value of `nvim` instead of `neovim`

[ert485]

Steps to Reproduce:

• download a generate.vim from https://vim-bootstrap.com/ after choosing "neovim" and "go"
• open vim

Symptoms and Debugging:

Google results:

At this point I'm thinking "Ooookaaay, so why am I still getting vim settings even though I chose neovim"

Reason: The vimrc template checks for nvim:

...but index.htmls value for editor is neovim

Solution:

• use nvim in the html template, not neovim. This is what the value was before https://github.com/editor-bootstrap/vim-bootstrap/pull/381

[avelino]

Thanks @ert485