Fix thinko in superevent suffix description
Jolien pointed out there's a mistake in content section, it lists the suffixes as a, b, .., z, aa, ab, .., az, aaa, but aaa should be ba.
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Jolien pointed out there's a mistake in content section, it lists the suffixes as a, b, .., z, aa, ab, .., az, aaa, but aaa should be ba.