Fix #14, use json to store icons

[Freed-Wu]

According to https://github.com/ogham/exa/blob/master/src/output/icons.rs
add some icons

sort all json alphabetically

Because neovim/neovim#20757
Use '.' to replace '' to get default value

And, add icons for some directory, like exa:

[Freed-Wu]

Error: Command './configure --prefix=/Users/runner/vim-v8.2.0235 --with-features=huge --enable-fail-if-missing' exited non-zero status 1: configure: error: WRONG! uint32_t not defined correctly.

Some test failed. Why?

[lambdalisue]

Please split and organize your commit logically so that I can review the changes.

I'm sorry I thought multiple things are in one commit because PR describe several things but it seems things are quite small and can be put into a single commit. I'll review the changes.

[lambdalisue]

Some test failed. Why?

Never mind. It seems the failure is not caused by this PR but caused by GitHub macOS runner chage. I'll fix it

[lambdalisue]

LGTM

[lambdalisue]

Released. https://github.com/lambdalisue/nerdfont.vim/releases/tag/v1.4.0 Thanks for your contribution 🎉

[Freed-Wu]

You are welcome.

I still have some advice: Now the json is sorted alphabetically. If you think
sorted is better than unsorted, how about add a test to check if it is sorted
after every PR? If we don't have any test to ensure the sort, after many PRs,
they may be changed to unsorted.

[lambdalisue]

I still have some advice: Now the json is sorted alphabetically. If you think
sorted is better than unsorted, how about add a test to check if it is sorted
after every PR? If we don't have any test to ensure the sort, after many PRs,
they may be changed to unsorted.

I also worry about that. Could you add such CI and send me a PR? (I'll do otherwise but it would take time)

[Freed-Wu]

Could you add such CI

I'll take a try.