remove lsp-signature

it bothers when signature doc overlaps actual code

lua/lsp.lua

@@ -1,6 +1,5 @@
 local on_attach = function(client, bufnr)
     local utils = require('utils')
-    require'lsp_signature'.on_attach(client)
 
     utils.opt("o", "omnifunc", "v:lua.vim.lsp.omnifunc")
 

lua/plugins.lua

@@ -106,8 +106,6 @@ return require('packer').startup(function()
   -- Fugitive for Git
   use { 'tpope/vim-fugitive' }
 
-  use { 'ray-x/lsp_signature.nvim' }
-
   -- Airline status bar
   use { 'vim-airline/vim-airline' }
   use { 'vim-airline/vim-airline-themes' }