Allow creation of abstract class and @interface from "New Java Class" command

[ghokun]

Environment

• Operating System: Fedora 33 (Xfce) x86_64
• JDK version: OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.9.1+1)
• Visual Studio Code version: 1.51.1
• Java extension version: 0.71.0

Steps To Reproduce

1. Open a java project
2. Wait for the java language server to detect it
3. Click "Explorer" Tab
4. Select "JAVA PROJECTS" view
5. Right click on any project or package and select "New Java Class"

Current Result

Current extension provides class, interface or enum for Java <14 and class, interface, enum or record for Java >=14.

Expected Result

abstract class and @interface options could be added to current snippet lists as an enhancement.

Additional Informations

I was developing a project with lots of custom annotation and thought this would be a good addition to this extension.

I think the code that handles this snippet is here:

vscode-java/src/fileEventHandler.ts

Lines 121 to 125 in a7854a1

	} else if (!serverReady || await isVersionLessThan(emptyFiles[i].toString(), 14)) {
	snippets.push(`public \${1|class,interface,enum|} ${typeName} {`);
	} else {
	snippets.push(`public \${1|class ${typeName},interface ${typeName},enum ${typeName},record ${typeName}()|} {`);
	}