patch 8.2.2261: Vim9: boolean option gets string type

Problem:    Vim9: boolean option gets string type.
Solution:   Check for VAR_BOOL. (closes #7588)

src/testdir/test_vim9_expr.vim

@@ -2417,6 +2417,11 @@ def Test_expr7_option()
   &grepprg = test_null_string()
   assert_equal('', &grepprg)
   set grepprg&
+
+  # check matching type
+  var bval: bool = &tgc
+  var nval: number = &ts
+  var sval: string = &path
 enddef
 
 def Test_expr7_environment()

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2261,
 /**/
     2260,
 /**/

src/vim9compile.c

@@ -3173,7 +3173,8 @@ compile_get_option(char_u **arg, cctx_T *cctx)
     {
 	// include the '&' in the name, eval_option() expects it.
 	char_u	*name = vim_strnsave(start, *arg - start);
-	type_T	*type = rettv.v_type == VAR_NUMBER ? &t_number : &t_string;
+	type_T	*type = rettv.v_type == VAR_BOOL ? &t_bool
+			  : rettv.v_type == VAR_NUMBER ? &t_number : &t_string;
 
 	ret = generate_LOAD(cctx, ISN_LOADOPT, 0, name, type);
 	vim_free(name);