#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/purescript/ls.vim

@@ -41,6 +41,7 @@ endfunction
 
 call ale#linter#Define('purescript', {
 \   'name': 'purescript-language-server',
+\   'aliases': ['purescriptls'],
 \   'lsp': 'stdio',
 \   'executable': function('ale_linters#purescript#ls#GetExecutable'),
 \   'command': function('ale_linters#purescript#ls#GetCommand'),