patch 8.1.0582: text properties are not enabled

Problem:    Text properties are not enabled.
Solution:   Fix sizeof argument and re-enable the text properties feature.
            Fix memory leak.
diff --git a/src/version.c b/src/version.c
index 9a44976..a0ffd4e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    582,
+/**/
     581,
 /**/
     580,