#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/rust/analyzer.vim

@@ -28,6 +28,7 @@ endfunction
 
 call ale#linter#Define('rust', {
 \   'name': 'analyzer',
+\   'aliases': ['rust_analyzer'],
 \   'lsp': 'stdio',
 \   'initialization_options': {b -> ale#Var(b, 'rust_analyzer_config')},
 \   'executable': {b -> ale#Var(b, 'rust_analyzer_executable')},