Completion menu not poping up #403

set relativenumber
set nu
set hidden
set incsearch
set scrolloff=6
set termguicolors
set shiftwidth=4
set tabstop=2
set softtabstop=2
syntax enable
set smartindent
set clipboard+=unnamedplus
filetype plugin indent on
set signcolumn=yes
set expandtab
set cursorline
set nowrap

set completeopt=menuone,noinsert,noselect
set shortmess+=c

call plug#begin('~/.vim/plugged')
Plug 'phanviet/vim-monokai-pro'
Plug 'neovim/nvim-lspconfig'
Plug 'nvim-lua/completion-nvim'
Plug 'preservim/nerdcommenter'
Plug 'preservim/nerdtree'
Plug 'OmniSharp/omnisharp-vim'
call plug#end()

colorscheme monokai_pro
highlight Normal guibg=none
highlight EndOfBuffer guibg=none

lua <<EOF

local nvim_lsp = require'lspconfig'
local pid = vim.fn.getpid()
local omnisharp_bin = "/usr/bin/omnisharp"
local attach_callback = require'completion'.on_attach

nvim_lsp.rust_analyzer.setup({ on_attach=attach_callback })
nvim_lsp.clangd.setup({ on_attach=attach_callback })
nvim_lsp.omnisharp.setup{
    cmd = { omnisharp_bin, "--languageserver" , "--hostPID", tostring(pid) };
    on_attach=attach_callback
}
nvim_lsp.cmake.setup{ on_attach=attach_callback }

vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
  vim.lsp.diagnostic.on_publish_diagnostics, {
    virtual_text = true,
    signs = true,
    update_in_insert = true,
  }
)
EOF

" ====== KEYBINDS ======
let mapleader = " "

" lsp
nnoremap <silent> gd <cmd>lua vim.lsp.buf.definition()<CR>
nnoremap <silent> <leader>h <cmd>lua vim.lsp.buf.hover()<CR>
nnoremap <silent> gD <cmd>lua vim.lsp.buf.implementation()<CR>
nnoremap <silent> <leader>r <cmd>lua vim.lsp.buf.references()<CR>
nnoremap <silent> <leader>d <cmd>lua vim.lsp.buf.declaration()<CR>
nnoremap <silent> <leader>a <cmd>lua vim.lsp.buf.code_action()<CR>
nnoremap <silent> <leader>[ <cmd>lua vim.lsp.diagnostic.goto_prev()<CR>
nnoremap <silent> <leader>] <cmd>lua vim.lsp.diagnostic.goto_next()<CR>

" nerd commenter
nnoremap <silent> <leader>cc <cmd>NERDCommenterComment<CR>
nnoremap <silent> <leader>cu <cmd>NERDCommenterUncomment<CR>

" nerd tree
nnoremap <silent> <leader>t <cmd>NERDTreeToggle<CR>