patch 8.1.2299: ConPTY in MS-Windows 1909 is still wrong

Problem:    ConPTY in MS-Windows 1909 is still wrong.
Solution:   Use same solution as for 1903. (Nobuhiro Takasaki, closes #5217)
diff --git a/src/misc2.c b/src/misc2.c
index 67fa8b5..8903b0d 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -4456,7 +4456,7 @@
  * 0: As usual.
  * 1: Windows 10 version 1809
  *      The bug causes unstable handling of ambiguous width character.
- * 2: Windows 10 version 1903
+ * 2: Windows 10 version 1903 & 1909
  *      Use the wrong result because each result is different.
  * 3: Windows 10 insider preview (current latest logic)
  */