patch 8.2.3238: Vim9: error message does not indicate the location

Problem:    Vim9: error message does not indicate the location.
Solution:   Add the relevant text. (issue #8634)

Author: brammool

src/errors.h

@@ -639,3 +639,5 @@ EXTERN char e_list_or_dict_required_for_argument_nr[]
 	INIT(= N_("E1227: List or Dictionary required for argument %d"));
 EXTERN char e_list_or_dict_or_blob_required_for_argument_nr[]
 	INIT(= N_("E1228: List or Dictionary or Blob required for argument %d"));
+EXTERN char e_expected_dictionary_for_using_key_str_but_got_str[]
+	INIT(= N_("E1229: Expected dictionary for using key \"%s\", but got %s"));

src/testdir/test_vim9_expr.vim

@@ -3114,7 +3114,7 @@ func Test_expr7_fails()
   call CheckDefExecAndScriptFailure(["var x = +g:alist"], 'E745:', 1)
   call CheckDefExecAndScriptFailure(["var x = +g:adict"], 'E728:', 1)
 
-  call CheckDefAndScriptFailure2(["var x = ''", "var y = x.memb"], 'E715:', 'E488:', 2)
+  call CheckDefAndScriptFailure2(["var x = ''", "var y = x.memb"], 'E1229: Expected dictionary for using key "memb", but got string', 'E488:', 2)
 
   call CheckDefAndScriptFailure2(["'yes'->", "Echo()"], 'E488: Trailing characters: ->', 'E260: Missing name after ->', 1)
 

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3238,
 /**/
     3237,
 /**/

src/vim9compile.c

@@ -2177,7 +2177,11 @@ generate_STRINGMEMBER(cctx_T *cctx, char_u *name, size_t len)
     type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
     if (type->tt_type != VAR_DICT && type != &t_any)
     {
-	emsg(_(e_dictreq));
+	char *tofree;
+
+	semsg(_(e_expected_dictionary_for_using_key_str_but_got_str),
+					       name, type_name(type, &tofree));
+	vim_free(tofree);
 	return FAIL;
     }
     // change dict type to dict member type