refactor: remove useless return value in documentClosed

Author: rubenporras

org.eclipse.lsp4e/src/org/eclipse/lsp4e/DocumentContentSynchronizer.java

@@ -356,7 +356,7 @@ public void documentSaved(IFileBuffer buffer) {
 
 	}
 
-	public CompletableFuture<@Nullable Void> documentClosed() {
+	public void documentClosed() {
 	   final var identifier = LSPEclipseUtils.toTextDocumentIdentifier(fileUri);
 		WILL_SAVE_WAIT_UNTIL_TIMEOUT_MAP.remove(identifier.getUri());
 		// When LS is shut down all documents are being disconnected. No need to send
@@ -365,7 +365,6 @@ public void documentSaved(IFileBuffer buffer) {
 			final var params = new DidCloseTextDocumentParams(identifier);
 			languageServerWrapper.sendNotification(ls -> ls.getTextDocumentService().didClose(params));
 		}
-		return CompletableFuture.completedFuture(null);
 	}
 
 	/**

org.eclipse.lsp4e/src/org/eclipse/lsp4e/LanguageServerWrapper.java

@@ -876,10 +876,9 @@ private boolean supportsWorkspaceFolderCapability() {
 	 */
 	public @Nullable CompletableFuture<@Nullable Void> disconnect(URI uri) {
 		DocumentContentSynchronizer documentListener = this.connectedDocuments.remove(uri);
-		CompletableFuture<@Nullable Void> documentClosedFuture = null;
 		if (documentListener != null) {
 			documentListener.getDocument().removePrenotifiedDocumentListener(documentListener);
-			documentClosedFuture = documentListener.documentClosed();
+			documentListener.documentClosed();
 			disconnectTextFileBuffer(uri);
 		}
 		if (this.connectedDocuments.isEmpty()) {
@@ -889,7 +888,7 @@ private boolean supportsWorkspaceFolderCapability() {
 				stop();
 			}
 		}
-		return documentClosedFuture;
+		return CompletableFuture.completedFuture(null);
 	}
 
 	private static void disconnectTextFileBuffer(URI uri) {