fix: fix handling of abstract methods in outline

[peternhale]

When document symbols are requested from the apex LS for an Apex class with abstract methods, it did not take into account an empty method body.

The LS update now handles this condition properly

@W-15593844@, #5553

Given the Apex class

public abstract class my {
    public my() {

    }
    public String s1() {
        return 's1';
    }

    public abstract String s2();
}

Functionality Before

Functionality After

[mingxuanzhangsfdx]

Thanks for the fix! LGTM

[diyer]

Hi @peternhale , can we create a work item in our automation epic to have an end to end test for outline use case?