It's really useful thing and helps avoid tpyos that break the cdoe.
There are already issues for that: https://github.com/christopho/solarus-quest-editor/issues/125 and https://github.com/christopho/solarus-quest-editor/issues/99
Are you sure that guy didn't mean syntax coloring (which is already there)? I mean, that post you linked to is kinda vague.
Yes, he says "recognition of syntax errors".