For that specific example you could have changed the title to simply be :
Understanding Python indentation
There is a reason that those words are not allowed in titles - they are ambiguous and are in essence why the post exists in the first place. If there was no "problem" or "question" then there would be no post.
I'm also not sure how the system would react to you adding/fixing/correcting one of those "banned" words in the title... It might not let you submit your edit...
In any case don't correct those mistakes unless you can see an opportunity to fix more problems with the post. Check for other spelling issues, mis-tagging, formatting, user signatures, etc...
Such minor edits just junk up the edit history.
Your heart and head are in the right place - you want to make the site better. You want it to be easy to understand other user's questions and allow people searching on Google to find the correct material they are looking for. However many many minor edits are just not worth it.
As was pointed out to me, quality filters and blacklisted words may vary across the SE network.
On physics.se for example, the word "problem" is not blacklisted.