patch 8.2.0122: readme files still mention MS-DOS

Problem:    Readme files still mention MS-DOS.
Solution:   Update readme files. (Ken Takata, closes #5486)
diff --git a/src/version.c b/src/version.c
index e26d15e..737b574 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    122,
+/**/
     121,
 /**/
     120,