patch 9.0.2055: Vim9: non-consistent error messages

Problem:  Vim9: non-consistent error messages
Solution: make error messages more consistent with common structure

Adjust vim9class messages to follow common pattern.
[Variable|Method] "var-or-meth-name" ... class "class-name"

closes: #13391

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Ernie Rael <errael@raelity.com>
diff --git a/src/vim9class.c b/src/vim9class.c
index a93cb29..b3930b1 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -2974,8 +2974,8 @@
 		    method_name, cl->class_name);
     }
     else
-	semsg(_(e_method_not_found_on_class_str_str), cl->class_name,
-		method_name);
+	semsg(_(e_method_not_found_on_class_str_str), method_name,
+	        cl->class_name);
     vim_free(method_name);
 }
 
@@ -2993,8 +2993,8 @@
 	    semsg(_(e_class_variable_str_accessible_only_using_class_str),
 		    varname, cl->class_name);
 	else
-	    semsg(_(e_variable_not_found_on_object_str_str), cl->class_name,
-		    varname);
+	    semsg(_(e_variable_not_found_on_object_str_str), varname,
+		    cl->class_name);
     }
     else
     {