[quick fix] No quickfix suggestion for switch over sealed interfaces

[jubax]

I was pointed to the jdt.ui project for quick fix bugs. See eclipse-jdt/eclipse.jdt.core#3300. I copied and modified the quickfix-related part to this new issue.

If you have a class with a "sealed interface" then no appropriate case labels are generated for quick fix.

public class SealedInterfaceContentAssist {

	sealed interface Foo {
		record FooImpl_a(String x) implements Foo {
		}

		record FooImpl_b(String y, String z) implements Foo {
		}
	}

	public static void main(String[] args) {
		Foo foo = getFoo();
		switch (foo) { // <== No quickfix for creating the case labels
		}
	}

	private static Foo getFoo() {
		return new Foo.FooImpl_b("a", "b");
	}

}

This quick fix would be important because there also is no appropriate content assist for this case. And the syntax for complex cases makes it hard to type it.

The quick fix should generate

	public static void main(String[] args) {
		Foo foo = getFoo();
		switch (foo) {
			case FooImpl_a(String x) -> ;
			case FooImpl_b(String y, String z) -> ;
		}
	}