There would in some cases be an empty line between headers and the description -
that does not seem right.
There should also be an empty line between description and diff - but that was
missing.
These two mistakes would sometimes make it up for each other so we fix both at
once to just show the improvement.
Instead of writing an extra newline when writing a header line, write an extra
line when it not is written as a part of the description but is necessary
anyway.
The tests in test-annotate.t and test-import-git.t that relied on trailing
space in a file created by a here string is now masked by a literal 'EOL'
string that is removed.
