README.md: add a Nerd Font requirement

[dam9000]

Fixes nvim-lua/kickstart.nvim#700 A Nerd Font is required by:

• mini.statusline
• Lazy plugin manager
• Neo-tree.nvim - not enabled by default however instructions on how to add it are in the README

[tjdevries]

Hmm, I think it might be better to try and disable the nerdfonts by default for mini and lazy. Do you by any chance happen to know how to do that? Otherwise I will look.

[dam9000]

I think I do, I can open a PR for that, although to be honest I like the look of nerd font icons better.

[dam9000]

Here: https://github.com/nvim-lua/kickstart.nvim/pull/711

[feoh]

I really love the look of nerd font, icons too! Why are we getting rid of that again?

I guess asking people to download and install fonts is an extra step. Let's just make them easy to turn back on again for those of us who love them and have them installed by default as the first thing we do when we come to a new system :-)

[dam9000]

@feoh that's an excellent suggestion, so I made a new PR which makes the nerd font an optional requirement and allows you to enable it with a simple global flag, please consider merging this instead: https://github.com/nvim-lua/kickstart.nvim/pull/716

[dam9000]

Closing this since a better alternative was merged.