avoid user-level 'Specification.definition' for internal constructions (to avoid e.g. automatic code generation behavior)

 src/Pure

 src/FOL

 src/HOL

 src/ZF

 src/CCL

 src/CTT

 src/Cube

 src/FOLP

 src/LCF

 src/Sequents

 src/Doc

 src/Tools