Fix Spelling Error in 2.4 Specification

In the 2.4 Genre List (derived from 2.3) there has been a long time spelling error which has impacted software developers that have used the 2.3 Specification. I know of no reason why this spelling error should not be corrected and it should have little or no impact but instead benefit applications that use the spec because they will not have to deal with bug reports about the misspelling.