Fix #1859 - Make the connection ID available on the connection object

autoload/ale/lsp.vim

@@ -24,6 +24,7 @@ function! ale#lsp#Register(executable_or_address, project, init_options) abort
         " capabilities_queue: The list of callbacks to call with capabilities.
         " capabilities: Features the server supports.
         let s:connections[l:conn_id] = {
+        \   'id': l:conn_id,
         \   'is_tsserver': 0,
         \   'data': '',
         \   'root': a:project,