nvim: add symbol outline hotkey

.config/nvim/lua/blake/plugins.lua

@@ -134,6 +134,7 @@ return require('packer').startup({function()
       'simrat39/symbols-outline.nvim',
       config = function()
          vim.cmd 'command! SO SymbolsOutline'
+         vim.cmd 'nnoremap <Leader>so <cmd>SymbolsOutline<CR>'
       end,
    }
    use {                                           -- ALE: Support for lots of linters, etc