Fix common colorization issue in class/interface declaration.

[hoanhtien]

Before:

After:

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[zhengbli]

Does this cover the following case (from ts spec):

interface KeyValuePair<K, V> extends Array<K | V> { 0: K; 1: V; }

and

interface G<T, U extends Function> {  
    f<V extends U>(x: V): V;  
}

[hoanhtien]

There is a small problem with type argument i.e. <K | V> in the example above. This is fixed in the commit below.

[hoanhtien]

The new commit fixes all scenarios in #226.

[zhengbli]

👍