Replace coc.nvim with ALE/vim-lsp/etc

So far, using `coc.nvim` and associated plugins wasn't working very well
and also wasn't particuarly very ergonomic to work with.

This replaces that with ALE (what was used before), adds `vim-lsp` (with
`vim-lsp-settings` to make configuration easier) and introduces
`asyncomplete` for autocompletion, a setup which seems to work quite
well.

So far, the only manual setup has been needed for Ruby, where
`solargraph` is preferred.

https://github.com/dense-analysis/ale
https://github.com/prabirshrestha/vim-lsp
https://github.com/mattn/vim-lsp-settings
https://github.com/prabirshrestha/asyncomplete.vim

Author: nickcharlton

vimrc

@@ -108,27 +108,6 @@ let g:ctrlp_use_caching = 0
 let g:ctrlp_working_path_mode = 'ra'
 let g:ctrlp_switch_buffer = 'et'
 
-""""""""""""
-" coc.nvim "
-""""""""""""
-" use tab to trigger completion and pick the selected
-inoremap <silent><expr> <TAB>
-      \ coc#pum#visible() ? coc#pum#next(1) :
-      \ CheckBackspace() ? "\<Tab>" :
-      \ coc#refresh()
-inoremap <expr><S-TAB> coc#pum#visible() ? coc#pum#prev(1) : "\<C-h>"
-
-inoremap <silent><expr> <CR> coc#pum#visible() ? coc#pum#confirm()
-                              \: "\<C-g>u\<CR>\<c-r>=coc#on_enter()\<CR>"
-
-function! CheckBackspace() abort
-  let col = col('.') - 1
-  return !col || getline('.')[col - 1]  =~# '\s'
-endfunction
-
-" format the current file with <leader>p
-nmap <leader>p :CocCommand prettier.formatFile<CR>
-
 """"""""""""""""""""
 " Filetype Plugins "
 """"""""""""""""""""
@@ -167,8 +146,18 @@ let g:pandoc#formatting#mode = 'ha' " enable auto hard wrapping
 let g:pandoc#formatting#smart_autoformat_on_cursormoved = 1
 let g:pandoc#syntax#conceal#use = 0 " disable conceal
 
-" enable airline with ALE
-let g:airline#extensions#ale#enabled = 1
+" custom lsp configuration
+let g:lsp_settings_filetype_ruby = ['solargraph']
+
+" setup tab complete
+inoremap <expr> <Tab>   pumvisible() ? "\<C-n>" : "\<Tab>"
+inoremap <expr> <S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"
+inoremap <expr> <cr>    pumvisible() ? asyncomplete#close_popup() : "\<cr>"
+
+let g:airline#extensions#ale#enabled = 1 " set ale to use airline
+let g:ale_virtualtext_cursor = 'current' " show error/warning text on current
+nmap <silent> <C-[> <Plug>(ale_previous_wrap)
+nmap <silent> <C-]> <Plug>(ale_next_wrap)
 
 " vim-test mappings
 nnoremap <silent> <Leader>t :TestFile<CR>

vimrc.bundles

@@ -22,21 +22,18 @@ call plug#begin('~/.vim/bundle')
 
 " Define bundles via Github repos
 Plug 'airblade/vim-gitgutter'
-Plug 'bmatcuk/coc-stylelintplus', {'do': 'yarn install --frozen-lockfile'}
 Plug 'bogado/file-line'
 Plug 'ctrlpvim/ctrlp.vim'
+Plug 'dense-analysis/ale'
 Plug 'janko-m/vim-test'
 Plug 'jeffkreeftmeijer/vim-dim'
-Plug 'neoclide/coc-css', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc-eslint', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc-html', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc-json', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc-prettier', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc-solargraph', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc-tsserver', {'do': 'yarn install --frozen-lockfile'}
-Plug 'neoclide/coc.nvim', { 'branch': 'release' }
+Plug 'mattn/vim-lsp-settings'
 Plug 'pbrisbin/vim-mkdir'
+Plug 'prabirshrestha/asyncomplete-lsp.vim'
+Plug 'prabirshrestha/asyncomplete.vim'
+Plug 'prabirshrestha/vim-lsp'
 Plug 'reedes/vim-lexical'
+Plug 'rhysd/vim-lsp-ale'
 Plug 'ruanyl/vim-gh-line'
 Plug 'sbdchd/vim-run'
 Plug 'sebdah/vim-delve'