censor: reduce risk of censor test blowing up output limit
The censored file is really big, and we keep using `hg cat` on it, with the
assumption that it is censored. However, when it is not censored, the amount of
extra line output is huge and quickly saturate the backlog of terminal and CI
system.
Differential Revision: https://phab.mercurial-scm.org/D10788
edition = "2018"
max_width = 79
wrap_comments = true
error_on_line_overflow = true