patch 8.2.3846: no error when using control character for 'lcs' or 'fcs'

Problem:    No error when using control character for 'lcs' or 'fcs'.
Solution:   Use char2cells() to check the width. (closes #9369)
diff --git a/src/version.c b/src/version.c
index 262a330..92612d5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3846,
+/**/
     3845,
 /**/
     3844,