Update completion resolve data for Javadoc completion

[JessicaJHee]

When a completion is triggered for javadoc, completionItem/resolve tries to resolve the proposal when we don't set the proposal for javadoc completion, which results in the following exception:

[Error - 11:01:42 AM] Request completionItem/resolve failed.
  Message: Internal error.
  Code: -32603 
java.util.concurrent.CompletionException: java.lang.IllegalStateException: Invalid completion proposal
	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:332)
	at java.base/java.util.concurrent.CompletableFuture.uniAcceptNow(CompletableFuture.java:747)
	at java.base/java.util.concurrent.CompletableFuture.uniAcceptStage(CompletableFuture.java:735)
	at java.base/java.util.concurrent.CompletableFuture.thenAccept(CompletableFuture.java:2182)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleRequest(RemoteEndpoint.java:279)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.consume(RemoteEndpoint.java:190)
	at org.eclipse.jdt.ls.core.internal.ParentProcessWatcher.lambda$1(ParentProcessWatcher.java:144)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.handleMessage(StreamMessageProducer.java:194)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:94)
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:113)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.IllegalStateException: Invalid completion proposal
	at org.eclipse.jdt.ls.core.internal.handlers.CompletionResolveHandler.resolve(CompletionResolveHandler.java:111)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.resolveCompletionItem(JDTLanguageServer.java:622)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.lambda$null$0(GenericEndpoint.java:65)
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.request(GenericEndpoint.java:120)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleRequest(RemoteEndpoint.java:261)
	... 10 more

[rgrunber]

The change looks fine to me and fixes the issue. I don't even think we really need a testcase given that the behaviour remains the same.

I would just rename the commit since this doesn't prevent resolve (it still occurs). It prevents resolve from using incorrect request/proposal data.

[rgrunber]

retest this please.