Help people learn that the Essay question type can be used for file upload

The Essay help string that appears in the question-type chooser (pluginname_help | qtype_essay) could be improved.

Currently it reads:

{blockquote}
In response to a question (that may include an image) the respondent writes an answer of a paragraph or two. The essay question will not be assigned a grade until it has been reviewed by a teacher and manually graded.{blockquote}

Other systems have a separate question type called something like "File response". See, for example, https://moodle.org/mod/forum/discuss.php?d=280281, but people do not realise that the Moodle Essay type can be used in the same way.

I'll put a suggestion into en_fix, but I thought it would be easier to discuss it with tsala and maryc here first.

I can't do a suggestion now. I have to go and get a bus.