Allowing edits of less than 6 characters in code blocks might not be a bad idea for answers, but
it may be problematic for questions.
Don't take me the wrong way, I'm not a big fan of the 6 character rule, as I've seen editors do some strange and irritating things to meet the requirement, (I saw someone edit in the word "link" after a link, just so they could remove a comma).
I've seen a few questions where the reason the OP was asking about their code ended up being as simple as a missing curly brace, comma, semicolon, or what have you.
In these cases a suggestion to add the missing character would be a great comment, or possibly an acceptable answer.
Notice that I said an acceptable answer not a great answer.
If these corrections are edited into the question then it could leave a non-sense question asking whats wrong with perfectly working code.