patch 8.1.0636: line2byte() gives wrong values with text properties

Problem:    line2byte() gives wrong values with text properties. (Bjorn Linse)
Solution:   Compute byte offsets differently when text properties were added.
            (closes #3718)

src/version.c

@@ -799,6 +799,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    636,
 /**/
     635,
 /**/