#4607 No conflicts with nvim-lspconfig by default

Default `g:ale_disable_lsp` to a new mode `'auto'` by default. With this
setting applied, ALE will now check for the presence of nvim-lspconfig
and automatically turn off particular LSP linters if already configured
via nvim-lspconfig.

For users that do not use `nvim-lspconfig`, everything should work as
before.

ale_linters/elm/ls.vim

@@ -10,13 +10,13 @@ call ale#Set('elm_ls_elm_format_path', '')
 call ale#Set('elm_ls_elm_test_path', '')
 call ale#Set('elm_ls_elm_analyse_trigger', 'change')
 
-function! elm_ls#GetRootDir(buffer) abort
+function! ale_linters#elm#ls#GetProjectRoot(buffer) abort
     let l:elm_json = ale#path#FindNearestFile(a:buffer, 'elm.json')
 
     return !empty(l:elm_json) ? fnamemodify(l:elm_json, ':p:h') : ''
 endfunction
 
-function! elm_ls#GetOptions(buffer) abort
+function! ale_linters#elm#ls#GetOptions(buffer) abort
     return {
     \   'elmPath': ale#Var(a:buffer, 'elm_ls_elm_path'),
     \   'elmFormatPath': ale#Var(a:buffer, 'elm_ls_elm_format_path'),
@@ -26,7 +26,8 @@ function! elm_ls#GetOptions(buffer) abort
 endfunction
 
 call ale#linter#Define('elm', {
-\   'name': 'elm_ls',
+\   'name': 'ls',
+\   'aliases': ['elm_ls'],
 \   'lsp': 'stdio',
 \   'executable': {b -> ale#path#FindExecutable(b, 'elm_ls', [
 \       'node_modules/.bin/elm-language-server',
@@ -34,7 +35,7 @@ call ale#linter#Define('elm', {
 \       'elm-lsp'
 \   ])},
 \   'command': '%e --stdio',
-\   'project_root': function('elm_ls#GetRootDir'),
+\   'project_root': function('ale_linters#elm#ls#GetProjectRoot'),
 \   'language': 'elm',
 \   'initialization_options': function('elm_ls#GetOptions')
 \})