nac3core: type inferencer fix the pass statement

nac3core/src/toplevel/test.rs

@@ -939,7 +939,7 @@ fn test_analyze(source: Vec<&str>, res: Vec<&str>) {
         indoc! {"
             class A:
                 def fun(self):
-                    1 + 2
+                    pass
         "},
         indoc!{"
             class B:

nac3core/src/typecheck/type_inferencer/mod.rs

@@ -128,7 +128,7 @@ impl<'a> fold::Fold<()> for Inferencer<'a> {
                 }
             }
             ast::StmtKind::AnnAssign { .. } | ast::StmtKind::Expr { .. } => {}
-            ast::StmtKind::Break | ast::StmtKind::Continue => {}
+            ast::StmtKind::Break | ast::StmtKind::Continue | ast::StmtKind::Pass => {}
             ast::StmtKind::Return { value } => match (value, self.function_data.return_type) {
                 (Some(v), Some(v1)) => {
                     self.unify(v.custom.unwrap(), v1, &v.location)?;