Configure lspkind for the only completion provider available

Since lspkind is now being used by just one completion provider (the
only one remaining) the configuration is now taking place when loading
such provider.

nvim/language_server.vim

@@ -37,6 +37,9 @@ EOF
 
 lua << EOF
 local nvim_lsp = require('lspconfig')
+-- lspkind-nvim
+cmp_format = require('lspkind').cmp_format({with_text=false, preset='codicons',
+             menu=({nvim_lsp = "[LSP]", buffer = "[Buffer]", path = "[Path]"})})
 
 local on_attach = function(client, bufnr)
   vim.api.nvim_command('autocmd CursorHoldI <buffer> lua vim.lsp.diagnostic.show_line_diagnostics({show_header = false})')
@@ -48,6 +51,7 @@ local on_attach = function(client, bufnr)
       }
   )
   require('cmp').setup({
+    formatting = {format = cmp_format},
     sources = {{name = 'nvim_lsp'}, {name = 'buffer'}, {name = 'path'}},
   })
   lsp_mappings()
@@ -72,6 +76,3 @@ autocmd FileType gitcommit lua require'cmp'.setup.buffer {
 \     { name = 'path' },
 \   },
 \ }
-
-" lspkind-nvim
-lua require('lspkind').init({with_text=false, preset='codicons'})