I don't think there's any effect at all. Just by highlighting the text, it seems the space is removed from the formatted text anyway. The lines of text in the next section form a conclusive test, assuming meta's formatting is the same as the main site's for leading spaces. A single leading space has no effect, though multiple spaces can change the formatting.
Test: this line was typed with a leading space.
Test: this line was typed with no leading spaces.
Test: this line was typed with several leading spaces.
At the editor's rep count of 5K+, I don't think editing points are awarded.
Also, the question isn't closed, but editing answers doesn't push questions onto the reopen queue.
Stack exchange has lots of seemingly-undocumented features, so there may be a side-effect we've not considered that the editor was counting on. It could also be as innocent as an accidental mouse-click.
You may have to pose a question to the editor if you want to know :) . Post back here if you find out.