Self closing tag causes NPE in cvc_complex_type_2_1CodeAction.doCodeAction

[fbricon]

At the root of lsp4xml (with money.xsd present), create a file with :

<money xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="org.eclipse.lsp4xml/src/test/resources/xsd/money.xsd" currency="euros"> </money>

When self closing the money tag, an NPE is thrown:

Error - 3:22:55 p.m.] Apr 03, 2019 03:22:55 org.eclipse.lsp4j.jsonrpc.RemoteEndpoint fallbackResponseError()
Message: Internal error: java.lang.NullPointerException
java.util.concurrent.CompletionException: java.lang.NullPointerException
	at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:273)
	at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:280)
	at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:604)
	at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: java.lang.NullPointerException
	at org.eclipse.lsp4xml.extensions.contentmodel.participants.codeactions.cvc_complex_type_2_1CodeAction.doCodeAction(cvc_complex_type_2_1CodeAction.java:42)
	at org.eclipse.lsp4xml.extensions.contentmodel.participants.ContentModelCodeActionParticipant.doCodeAction(ContentModelCodeActionParticipant.java:45)
	at org.eclipse.lsp4xml.services.XMLCodeActions.doCodeActions(XMLCodeActions.java:43)
	at org.eclipse.lsp4xml.services.XMLLanguageService.doCodeActions(XMLLanguageService.java:188)
	at org.eclipse.lsp4xml.XMLTextDocumentService.lambda$codeAction$15(XMLTextDocumentService.java:340)
	at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
	... 6 more