Previously we used a
EmailCook.url_regexp this regex used lookbehinds
Unfortunately certain strings could lead to pathological behavior causing CPU to skyrocket and regex replace to take a very very long time.
EmailCook still needs a fix, but it is less urgent cause it already splits to single lines. That said we will correct that as well in a seperate PR.
New implementation is far more naive and relies on the extra spaces search indexer inserts.