Added a space after "for"

For consistency with the rest of the document and the "coding style" chapter

1-js/04-object-basics/01-object/article.md

@@ -339,7 +339,7 @@ To walk over all keys of an object, there exists a special form of the loop: `fo
 The syntax:
 
 ```js
-for(key in object) {
+for (key in object) {
   // executes the body for each key among object properties
 }
 ```
@@ -353,7 +353,7 @@ let user = {
   isAdmin: true
 };
 
-for(let key in user) {
+for (let key in user) {
   // keys
   alert( key );  // name, age, isAdmin
   // values for the keys
@@ -363,7 +363,7 @@ for(let key in user) {
 
 Note that all "for" constructs allow us to declare the looping variable inside the loop, like `let key` here.
 
-Also, we could use another variable name here instead of `key`. For instance, `"for(let prop in obj)"` is also widely used.
+Also, we could use another variable name here instead of `key`. For instance, `"for (let prop in obj)"` is also widely used.
 
 
 ### Ordered like an object
@@ -384,7 +384,7 @@ let codes = {
 };
 
 *!*
-for(let code in codes) {
+for (let code in codes) {
   alert(code); // 1, 41, 44, 49
 }
 */!*
@@ -442,7 +442,7 @@ let codes = {
   "+1": "USA"
 };
 
-for(let code in codes) {
+for (let code in codes) {
   alert( +code ); // 49, 41, 44, 1
 }
 ```
@@ -720,7 +720,7 @@ To access a property, we can use:
 Additional operators:
 - To delete a property: `delete obj.prop`.
 - To check if a property with the given key exists: `"key" in obj`.
-- To iterate over an object: `for(let key in obj)` loop.
+- To iterate over an object: `for (let key in obj)` loop.
 
 Objects are assigned and copied by reference. In other words, a variable stores not the "object value", but a "reference" (address in memory) for the value. So copying such a variable or passing it as a function argument copies that reference, not the object. All operations via copied references (like adding/removing properties) are performed on the same single object.