For strings containing escaped newlines (\n), always start a new line
right before that sequence and remove any other whitespace in between.
Let the closing </string> tag follow immediately on the last line.
Keep one-line translations on one line, without arbitrary wrapping.
Actually fix some line-break inconsistencies within the translations
along the way. Some had questionable \n\ sequences, capitalized \N or
the n actually forgotten after an escaping backslash, which lead to
parsing errors. Others simply used two line breaks (which are
collapsed to one space during parsing) instead of the needed \n escape
sequence.
This gets the format much closer to what Weblate generates when
dumping the parsed strings into fresh XML files. Also harmonizes the
formatting in the "source" (English) values/strings.xml though.
