This plugin connect the completion support between prabirshrestha/vim-lsp and ncm2/ncm2.
Plug 'prabirshrestha/vim-lsp'
Plug 'ncm2/ncm2-vim-lsp'
For registering language servers, please read the documentation of vim-lsp.
Particular servers can be excluded by including their name (as configured
in vim-lsp) in the list g:ncm2_vim_lsp_blocklist
. e.g.
let g:ncm2_vim_lsp_blocklist = ['jedi-language-server','efm-language-server']