There is an answer to my question in which the user typed recovation. I can't change it to revocation because of limits of Stack Exchange. Why do we need those limits???
We have restrictions so that spam isn't edited into posts mainly, but also so that people who don't know how sites work don't change things in unexpected ways simply because they are unaware of the rules and conventions.
We also want edits to be substantial and to correct everything that's wrong in a post. We don't want to have to do it in multiple passes.
Once you've enough rep to be trusted you can edit anything.
regarding that particular answer
it could stand to have info corrected to information
you could edit the link so that the words "this information" become the link itself rather than having the URL visible since the URL isn't something you really need to read inline. That will still allow the link to show on hover.
Those suggestions, together with the word you want to change will put you over the 6 character limit and allow you to submit your suggested edit.