Add Section 18.10 - No spaces inside brackets

See #593

README.md

@@ -1575,6 +1575,18 @@ Other Style Guides
     }
     ```
 
+  - [18.10](#18.10) <a name='18.10'></a> Do not add spaces inside brackets.
+
+    ```javascript
+    // bad
+    const foo = [ 1, 2, 3 ];
+    console.log(foo[ 0 ]);
+
+    // good
+    const foo = [1, 2, 3];
+    console.log(foo[0]);
+    ```
+
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 ## Commas