Fix for "Chapter 47. Calc Add-ins: 2.4. Problems with Office Types"

[stbergmann]

The description of https://bugs.documentfoundation.org/show_bug.cgi?id=152972#c0 “Javamaker fails with "unknown entity"” made me aware of the issue described at https://flywire.github.io/lo-p/47-Calc_Add-ins.html#24-problems-with-office-types, for which the fix should be to reference both the URE types.rdb and the LibreOffice offapi.rdb: In a LibreOffice 7.4 SDK environment on Linux, with the sample file from that section as test.idl,

$ idlc -I"$OO_SDK_HOME/idl" test.idl 
Compiling: test.idl
$ regmerge test.rdb /UCR test.urd 
$ javamaker -X"$OFFICE_PROGRAM_PATH/types.rdb" -X"$OFFICE_PROGRAM_PATH/types/offapi.rdb" test.rdb

successfully generates org/openoffice/doubler/XDoubler.class.