Re-enable completions (#113)

Summary:
4be1b3b disabled autocomplete by passing no completion provider to the client. However, I think the intention was to just remove the triggers, not disable all autocomplete. This re-enables this functionality.

Fixes #112

Pull Request resolved: #113

Reviewed By: stepancheg

Differential Revision: D53956003

Pulled By: ndmitchell

fbshipit-source-id: 0f060a9fe008897357af75b091f8092010b1c43f

starlark_lsp/src/server.rs

@@ -47,6 +47,7 @@ use lsp_types::request::GotoDefinition;
 use lsp_types::request::HoverRequest;
 use lsp_types::CompletionItem;
 use lsp_types::CompletionItemKind;
+use lsp_types::CompletionOptions;
 use lsp_types::CompletionParams;
 use lsp_types::CompletionResponse;
 use lsp_types::DefinitionOptions;
@@ -405,6 +406,7 @@ impl<T: LspContext> Backend<T> {
         ServerCapabilities {
             text_document_sync: Some(TextDocumentSyncCapability::Kind(TextDocumentSyncKind::FULL)),
             definition_provider,
+            completion_provider: Some(CompletionOptions::default()),
             hover_provider: Some(HoverProviderCapability::Simple(true)),
             ..ServerCapabilities::default()
         }