i18n: add--interactive: mark simple here-documents for translation

i18n: add--interactive: mark simple here-documents for translation

Mark messages in here-documents without interpolation for translation.

The here-document delimiter \EOF, which is the same as 'EOF', indicates
that the text is to be treated literally without interpolation of its
content.  Unfortunately xgettext is not able to extract here-documents
delimited with \EOF but it is with delimiter enclosed in single quotes.
So change \EOF to 'EOF', although in this case does not make
difference what variation of here-document to use since there is nothing
to interpolate.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>