patch 8.1.0746: highlighting not updated with conceal and 'cursorline'

Problem:    Highlighting not updated with conceal and 'cursorline'. (Jason
            Franklin)
Solution:   Do not use a zero line number.  Check if 'conceallevel' is set for
            the current window.
diff --git a/src/version.c b/src/version.c
index 60d82d2..4b21d28 100644
--- a/src/version.c
+++ b/src/version.c
@@ -796,6 +796,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    746,
+/**/
     745,
 /**/
     744,