ROOTS

receovered alternative abbrevs for \<open> \<close> from 8e8243975860, to accommodate national keyboard layouts where "`" might be hard to produce;

src/Pure
src/FOL
src/HOL
src/ZF
src/CCL
src/CTT
src/Cube
src/FOLP
src/LCF
src/Sequents
src/Doc
src/Tools