patch 8.1.0638: text property highlighting is off by one column

Problem:    Text property highlighting is off by one column. (Bjorn Linse)
Solution:   Update text property highlighting earlier.  Let it overrule syntax
            highlighting.

src/version.c

@@ -799,6 +799,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    638,
 /**/
     637,
 /**/