Dai Ha
011ee80067
Criterion 19 covers a block-scalar body whose key line falls outside
diff -u's default 3-line context (an 8-line body with only the 6th
line changed). Criterion 20 covers a blank line inside the value,
which used to reset the old indentation-anchored mask.
Both are RED against the pre-#639 redact() (git show 28ea0de) and
GREEN against the current one; each asserts both the secret's
absence and a non-secret control line's presence.