Shorten class context range by one line.
Class contexts behave in some ways (tooltips, completion) as if they're one line longer than they ought to be: ``` a = 2 class M: a = "text" b = a # tooltip of `a` says 'str', should be 'int' a # 'int' ``` Expression-visitor doesn't have that problem, i.e. `b` is 'int' in the example above. Shortening the class context range by one line fixes tooltips, uses and completions, and doesn't seem to break the expression visitor. Test case "class_scope_end_outside" is fixed by this patch, the others are unchanged. BUG: 309817