patch 8.2.1533: Vim9: error when passing getreginfo() result to setreg()

Problem:    Vim9: error when passing getreginfo() result to setreg().
Solution:   Use dict_get_bool() for "isunnamed". (closes #6784)

src/evalfunc.c

@@ -7427,7 +7427,7 @@ f_setreg(typval_T *argvars, typval_T *rettv)
 		regname = pointreg;
 	    }
 	}
-	else if (dict_get_number(d, (char_u *)"isunnamed"))
+	else if (dict_get_bool(d, (char_u *)"isunnamed", -1) > 0)
 	    pointreg = regname;
     }
     else

src/testdir/test_vim9_func.vim

@@ -1419,6 +1419,13 @@ def Test_setbufvar()
    setlocal ts=8
 enddef
 
+def Test_setreg()
+  setreg('a', ['aaa', 'bbb', 'ccc'])
+  let reginfo = getreginfo('a')
+  setreg('a', reginfo)
+  assert_equal(reginfo, getreginfo('a'))
+enddef 
+
 def Fibonacci(n: number): number
   if n < 2
     return n

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1533,
 /**/
     1532,
 /**/