[dev-context] structure commands

Hi Hans, what’s the for status the usage of the new structure code commands in mkiv? header have now the internal commands \definestrcuturehead and \setupstructurehead with \definehead and \setuphead as synonyms, should the former internal names ever be mentioned in the doku or lets pretend they do no exist (what i prefer) and mention only \define/\setuphead? a bigger problem seems to me the \definestructure(separatorset|prefixset|...) commands, the names are too long and it's weird to have commands with 'definestrcuture' in their name but no matching command with 'strcuture' in the name which use these settings. Wolfgang