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.

Author: brammool

src/ex_getln.c

@@ -504,7 +504,11 @@ may_adjust_incsearch_highlighting(
 	return FAIL;
 
     if (firstc == ccline.cmdbuff[skiplen])
+    {
 	pat = last_search_pattern();
+	skiplen = 0;
+	patlen = STRLEN(pat);
+    }
     else
 	pat = ccline.cmdbuff + skiplen;
 

src/version.c

@@ -794,6 +794,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    273,
 /**/
     272,
 /**/