Show less errors for code with syntax errors

[marat-rkh]

Suppose I am defining a function:

My caret is before the closing curly bracket. I know my code is incorrect, I need to write a type to fix it.

Expected: IDE shows me one error that says exactly that.

Actual: IDE spits way too many errors on me. The last 2 errors are incorrect, most of the rest are cryptic and confusing (<return expr wob> expected?):

I think it makes sense to reduce the amount of errors. One way to do that is to improve the recovery rules in the parser definition.