Remove empty highlight link for comments

Update README.md

* Add a list of `Features`
* Add `Usage` section
* Improve description
* Improve look
* Rearrange sections
* Add note about `gf`

Update README.md:

* Add info about installing using plugin managers
* State that neovim is also supported
* State that screenshots are made using my colorscheme
* Fix grammer

Improve README.md