evolve: fix use of "'%d' % ctx"
ctx has not been convertible to int since Mercurial commit
38f480502043 (context: remove basectx.__int__ (API), 2018-02-24). I
decided to use "%s" instead to match other similar messages in
evolvecmd.py. I also added a space to match the other messages.
syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
^tests/.*\.err$
^tests/easy_run.sh$
^build/
^dist/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes
^docs/training/graphs/
^docs/training/html/
^docs/training/index.html
^docs/training/graphviz-images/
^docs/training/img/
^docs/training/output/
^docs/training/pandocfilters/