Changes

Changes from Mercurial (hg https://foss.heptapod.net/isa-afp/afp-devel/ default)

Changeset 13458:fa0be72ed95f by paulson _lp15@cam.ac.uk_: A slight beautification
The file was modified	`thys/Irrationals_From_THEBOOK/Irrationals_From_THEBOOK.thy`