runtime(doc): fix typo in :h dos-colors

related: #15723
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/os_dos.txt b/runtime/doc/os_dos.txt
index 1b738f4..96ef39d 100644
--- a/runtime/doc/os_dos.txt
+++ b/runtime/doc/os_dos.txt
@@ -1,4 +1,4 @@
-*os_dos.txt*    For Vim version 9.1.  Last change: 2024 Apr 25
+*os_dos.txt*    For Vim version 9.1.  Last change: 2024 Sep 24
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -195,8 +195,8 @@
 	t_so	 31	 standout mode: White (15) text on DarkBlue (16)
 	t_se	  0	 standout mode end (revert to default)
 
-	t_czh	225	 italic mode: DarkBlue text (1) on Yellow (224)
-	t_czr	  0	 italic mode end (revert to default)
+	t_ZH	225	 italic mode: DarkBlue text (1) on Yellow (224)
+	t_ZR	  0	 italic mode end (revert to default)
 
 	t_us	 67	 underline mode: DarkCyan text (3) on DarkRed (64)
 	t_ue	  0	 underline mode end (revert to default)