private static CharSequence sliceFrom(IdlInternalTokenizer tokenizer, int startPosition, int endOffset) {
        return tokenizer.getModel(startPosition, tokenizer.getPosition() - endOffset);
    }
Expects that the tokenizer is on a relative or absolute shape ID, skips over it, and returns a borrowed slice
of the shape ID.

@param tokenizer Tokenizer to consume and advance.
@return Returns the borrowed shape ID.
smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlShapeIdParser.java