public final StringEquals stringEqual(String value) {
        return StringEquals.ofExpressions(toExpression(), Expression.of(value));
    }
Returns a StringEquals function of this expression and the given string value.

@param value the string value to compare this expression to.
@return the {@link StringEquals} function.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/language/syntax/SyntaxElement.java