patch 8.2.1532: compiler warning for conversion of size_t to long

Problem:    Compiler warning for conversion of size_t to long.
Solution:   Add type cast.

src/eval.c

@@ -5392,7 +5392,7 @@ string_slice(char_u *str, varnumber_T first, varnumber_T last)
     if (start_byte < 0)
 	start_byte = 0; // first index very negative: use zero
     if (last == -1)
-	end_byte = slen;
+	end_byte = (long)slen;
     else
     {
 	end_byte = char_idx2byte(str, slen, last);

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1532,
 /**/
     1531,
 /**/