Add a test for unicode regional indicator widths

kitty_tests/datatypes.py

@@ -338,6 +338,9 @@ class TestDataTypes(BaseTest):
         self.ae(tuple(map(w, 'a1\0コニチ ✔')), (1, 1, 0, 2, 2, 2, 1, 1))
         self.ae(wcswidth('\u2716\u2716\ufe0f\U0001f337'), 5)
         self.ae(wcswidth('\033a\033[2mb'), 2)
+        # Regional indicator symbols (unicode flags) are defined as having
+        # Emoji_Presentation so must have width 2
+        self.ae(tuple(map(w, '\U0001f1ee\U0001f1f3')), (2, 2))
         tpl = truncate_point_for_length
         self.ae(tpl('abc', 4), 3)
         self.ae(tpl('abc', 2), 2)