I have Custom Languages created using Xtext.
I want show a documentation with CodeCompletion(ctrl+space) using LSP and need to show it in Intellij.

Like forexample, here function a(): void is shown when we see autocompletion proposals.
Similarly I also want to do that.

I am using below code to set additionContentAssist in org.eclipse.xtext.ide.editor.contentassist.ContentAssistEntry

ContentAssistEntry entry = new ContentAssistEntry();
String additionalProposalInfo = configurableProposal.getAdditionalProposalInfo();
MarkupContent content = new MarkupContent(MarkupKind.MARKDOWN, additionalProposalInfo);
entry.setProposal(proposal);
entry.setDocumentation(content.toString());

In my case, additionalProposalInfo is some html kind of text

which I want to show in proper readable format.

Actually, In org.eclipse.xtext.ide.server.contentassist.ContentAssistService , we have this code
where completionItem.setDocumentation(String doc) needs String.
So, I just sent content.toString and that’s why its kind of plain String.
I don’t understand how should I send MarkupContent properly to this setDocumentation or what else should I do to show the content in proper readable format.