Warn users about manually copying citations #81
Description
Hi, thanks for the great work!
I am using the citation manager to write something where I needed to cite the same item twice. Hence, I just copied and pasted the <cite ..> </cite> section to where I needed it. However, after doing this, adding new citations stopped working. Looking at the console, I noticed the error
Uncaught (in promise) citeproc-js error: Previously referenced citationID lseb7 encountered in citationsPre
had shown up, where lseb7 is the id of the copied citation. And indeed, after removing the duplicated citation, and reinserting it again manually by using the interface, things stared working normally again.
I think it would be nice to add a warning for this case, since at least for me, it was not obvious that copying a citation to have it appear in multiple places does not work.