fix(schema): Jinja - show source line in error message (#6885)

Author: ovr

packages/cubejs-backend-native/src/python/template/entry.rs

@@ -28,6 +28,8 @@ impl<'a> NeonMiniJinjaContext for FunctionContext<'a> {
                 content += &format!("{:>4} | {}\r\n", idx + 1, line);
             }
 
+            content += &format!("{:>4} > {}\r\n", idx + 1, lines[idx].1);
+
             if let Some(_span) = err.range() {
                 // TODO(ovr): improve
                 content += &format!(

packages/cubejs-backend-native/test/__snapshots__/jinja.test.ts.snap

@@ -232,6 +232,7 @@ exports[`Jinja render template_error.jinja: template_error.jinja 1`] = `
    7 | 7
    8 | {%- for country in countries %}
    9 | 9
+  10 > {%- unexpected_block_name %}
      i ^^^^^^^^^^^^^^^^^^^^^^^^ syntax error
   11 | 11
   12 | 12