Vim + coc-deno in Deno docs

[Fernando Basso]

I thought it would be worth mentioning that Deno docs have a section about Vim and coc-deno. Great!

• denoland/deno#5499
• https://deno.land/manual/getting_started/setup_your_environment#vim-and-neovim

@fannheyward Thanks for your work!