Revisions should not url_encode or at least url_encode(diff("content"))

[ccoenen]

In #521 it looks like the Revisions table does something like this:

diff(url_encode("content"))

This makes little sense, as the diffing will always yield all of the document. And those are stored in lastContent and content anyway.

This should be reversed to be

url_encode(diff("content"))

I'm not even entirely sure why the url-encode is done in the first place, but it appears to be there.

[jackycute]

Hi @ccoenen
It's because the diff might contains invalid unicode pair which can cause serious problem.

Related to these lines of code:
https://github.com/hackmdio/diff-match-patch/blob/master/index.js#L1327
https://github.com/hackmdio/diff-match-patch/blob/master/index.js#L2187