If we're writing the body to standard output, we cannot know what the
filename of the corresponding header is going to be, but it seems
vanishingly unlikely that it will be either `stdout.h` (which we would
traditionally have generated) or `-.h` (which we would have generated
since !3886).
This makes some of the output snippets sufficiently short that black(1)
requires that they are folded into a single line.
Signed-off-by: Simon McVittie <smcv@collabora.com>
fc7942f46b
