Just to make this clear, the 6 characters limit is only related to suggested edits. Which means that after you reach 2000 reputation points, you can make shorter edits. I'd say that this is not very likely going to change. (This guess is based on plenty of past discussions about this issue both here
and on the main meta.)
If you are making suggested edit which does not go through because of character limit, you can:
- Check whether there is something more to be edited, which will get you over 6 characters.
- If you cannot find anything, simply point out in a comment that the post should be edited and what the typo is. (If you wish to clarify, you might add an explanation that you weren't able to make that edit because of character limit and less than 2k reputation.) There is quite a good chance that the OP or a user with edit privileges sees your comment and they will edit the post. (At least if they agree with your assessment that the post should be edited.)
Probably less optimal solution (but still possible, if for some reason you consider the edit important enough) would be mentioning this in chat - in order to get an attention of some user with edit privileges. Reasonable places to do this could be the main chat room or c-r-u-d-e. (The purpose of the latter is - among other things - discussions related to editing and improving posts; as you can probably guess from the room description.)
There were also suggestions to get through the limit by artificially adding something at the end of the post which does not change it that much. For example, adding
or something similar. (I think it was mentioned few times here on meta, I was able to find, for example this answer.) However, I do not think that this is a good suggestion. (Even the linked answer says that it "should only be used when absolutely necessary".) It goes against the spirit of what editing is supposed to do. (You should not try to trick the system which has some limits for a reason. And also adding unnecessary characters to a post is not good.) I'd say that if the reviewer checking your suggested edit is careful enough, a suggestion using this trick will probably be rejected.