check-code: grep's context flags don't need an extra space before number
A bit of useless trivia found while researching this: OpenBSD's grep's -C has a
default value (of 2) and disallows space before the argument (while -A and -B
allow).
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.