added space character after uploaded file's link as separator for multi-uploads; re #4068

git-svn-id: svn://develop.studip.de/studip/trunk@29574 c5b85792-5220-0410-ad23-ed5b6b8ad999
add documentation re #4063

git-svn-id: svn://develop.studip.de/studip/trunk@29575 c5b85792-5220-0410-ad23-ed5b6b8ad999