evolve: indent cmdnext and cmdprev ready for locking change (issue5244) The locking change I'm about to introduce forces an indentation shift. Do the indentation change with no code change now, to make the next change easier to review

syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
\.err$
^tests/easy_run.sh$
^build/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes