patch 8.1.0273: invalid memory access when using 'incsearch'

Problem:    Invalid memory access when using 'incsearch'.
Solution:   Reset "patlen" when using previous search pattern.
diff --git a/src/version.c b/src/version.c
index 68df1ec..510ce45 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    273,
+/**/
     272,
 /**/
     271,