parser: fix dump removing empty lines (#18452)

vlib/v/fmt/tests/empty_lines_expected.vv

@@ -10,6 +10,8 @@ fn squash_multiple_empty_lines() {
 
 	println('b')
 
+	dump('c')
+
 	c := 0
 
 	d := 0

vlib/v/fmt/tests/empty_lines_input.vv

@@ -8,6 +8,8 @@ fn squash_multiple_empty_lines() {
 
 	println('b')
 
+	dump('c')
+
 
 	c := 0
 

vlib/v/fmt/tests/empty_lines_keep.vv

@@ -33,12 +33,15 @@ fn keep_single_empty_line() {
 
 	println('c')
 
+	dump('d')
+
 	d := 0
 
 	if true {
 		println('e')
 	}
 
+	dump('f')
 	f := 0
 	arr << MyStruct{}
 

vlib/v/parser/expr.v

@@ -328,9 +328,11 @@ fn (mut p Parser) check_expr(precedence int) !ast.Expr {
 				p.next()
 			}
 			p.check(.rpar)
+			mut pos := p.tok.pos()
+			pos.update_last_line(p.prev_tok.line_nr)
 			node = ast.DumpExpr{
 				expr: expr
-				pos: spos.extend(p.tok.pos())
+				pos: spos.extend(pos)
 			}
 		}
 		.key_offsetof {