feat(belongsToMany): add source and target to belongs-to-many.js AssociationError (#9562)

lib/associations/belongs-to-many.js

@@ -61,7 +61,7 @@ class BelongsToMany extends Association {
     super(source, target, options);
 
     if (this.options.through === undefined || this.options.through === true || this.options.through === null) {
-      throw new AssociationError('belongsToMany must be given a through option, either a string or a model');
+      throw new AssociationError(`${source.name}.belongsToMany(${target.name}) requires through option, pass either a string or a model`);
     }
 
     if (!this.options.through.model) {

test/unit/associations/belongs-to-many.test.js

@@ -107,7 +107,7 @@ describe(Support.getTestDialectTeaser('belongsToMany'), () => {
       const errorFunction2 = User.belongsToMany.bind(User, Task, { through: undefined });
       const errorFunction3 = User.belongsToMany.bind(User, Task, { through: null });
       for (const errorFunction of [errorFunction1, errorFunction2, errorFunction3]) {
-        expect(errorFunction).to.throw(AssociationError, 'belongsToMany must be given a through option, either a string or a model');
+        expect(errorFunction).to.throw(AssociationError, `${User.name}.belongsToMany(${Task.name}) requires through option, pass either a string or a model`);
       }
     });
     it('throws an AssociationError for a self-association defined without an alias', () => {