patch 8.0.0212: buffer for key name may be too small

Problem:    The buffer used to store a key name theoreticaly could be too
            small. (Coverity)
Solution:   Count all possible modifier characters.  Add a check for the
            length just in case.
diff --git a/src/version.c b/src/version.c
index 8e33c96..741b8da 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    212,
+/**/
     211,
 /**/
     210,