fix: lspkind symbol

[eeeXun]

We should get icons from symbol_map

[stevearc]

I'm looking at lspkind and it still looks like it provides the lspkind.symbolic API to retrieve a symbol. Is there some reason why accessing symbol_map is better? Is the symbolic() API not working for you?

[eeeXun]

1. in this line. There is no mode "symbolic ". "symbolic " is not in modes. So in our current code, we will call modes["symbol"].

2. In modes["symbol"], it calls get_symbol(), and get_symbol() just returns lspkind.symbol_map.

Is the symbolic() API not working for you?

Yes, it works. But it works by coincidence.

Is there some reason why accessing symbol_map is better?

Yes, we don't need that recursive call.

BTW, the main reason of this PR is nvim-cmp separates icons and kind. So we no longer need symbolic() in lspkind. (I'm also planing create a PR here). And these changes will break this plugin. So, that's why I create this PR.