Better code completion for extends

I noticed that the code completion for after extends is a little rough.

Also extends is not even it's own Token? weird.

I'd expect these tests to pass:

describe('extends', () => {
        it('should show only other classes for a class', () => {
            program.setFile('source/main.bs', `
                class Klass1
                end class

                class Klass2 extends
                end class
            `);

            program.validate();
            //   class Klass2 extends |
            let completions = program.getCompletions('source/main.bs', util.createPosition(4, 37));
            expectCompletionsIncludes(completions, [{
                label: 'Klass1',
                kind: CompletionItemKind.Class
            }]);
            expect(completions.length).to.eql(1);
        });

        it('should show other interfaces and components for an interface', () => {

            program.setFile('components/myNode.xml',
                trim`<component name="myNode" extends="group">
                </component>
            `);

            program.setFile('source/main.bs', `
                interface IFace1
                end class

                interface IFace2 extends 
                end class
            `);

            program.validate();
            //   interface IFace2 extends |
            let completions = program.getCompletions('source/main.bs', util.createPosition(4, 42));
            expectCompletionsIncludes(completions, [{
                label: 'IFace1',
                kind: CompletionItemKind.Class
            }]);

            expectCompletionsIncludes(completions, [{
                label: 'roSGNodeMyNode',
                kind: CompletionItemKind.Interface
            }]);
        });

    });

Start with the completion path exercised by program.getCompletions in the supplied tests, and inspect how extends is tokenized and how class, interface, and component symbols are filtered. Use the two example cases as acceptance criteria: class completion should list only other classes, while interface completion should include interfaces and components.