docs: array initializers should be avoided (#5233)

* Update Category.ts

Array initialisers should be avoided

* Update app.ts

sample/sample8-self-referencing/app.ts

@@ -20,6 +20,7 @@ createConnection(options).then(connection => {
     category1.name = "category #1";
     
     let mainCategory = new Category();
+    mainCategory.manyCategories = [];
     mainCategory.name = "main category";
     mainCategory.oneCategory = category1;
     mainCategory.manyCategories.push(category1);

sample/sample8-self-referencing/entity/Category.ts

@@ -33,17 +33,17 @@ export class Category {
     @OneToMany(type => Category, category => category.oneManyCategory, {
         cascade: true
     })
-    oneManyCategories: Category[] = [];
+    oneManyCategories: Category[];
 
     @ManyToMany(type => Category, category => category.manyInverseCategories, {
         cascade: true
     })
     @JoinTable()
-    manyCategories: Category[] = [];
+    manyCategories: Category[];
 
     @ManyToMany(type => Category, category => category.manyCategories, {
         cascade: true
     })
-    manyInverseCategories: Category[] = [];
+    manyInverseCategories: Category[];
 
-}
+}