Update rule.md

rules/seal-your-classes-by-default/rule.md

@@ -29,19 +29,20 @@ Watch this video by Nick Chapsas, to see the performance benefits of sealing you
 
 ### Avoid unnecessary covariance checks in Array
 
-Arrays in .NET are covariant. This means arrays enable implicit conversion of an array of a more derived type to an array of a less derived type.
-This operation is not type safe. To make sure it’s type safe JIT checks the type of the object before an item is assigned which is a performance cost.
-When the array is an array of sealed types, JIT knows there won’t be any covariance involved when sealed types are used, so it skips covariance checks.
-This improves performance with arrays.
+Arrays in .NET are covariant. This means arrays enable implicit conversion of an array of a more derived type to an array of a less derived type. This operation is not type safe. To make sure it’s type safe JIT checks the type of the object before an item is assigned which is a performance cost.
 
-![Figure: Array covariance - sealed Vs non-sealed. See the next figure for performance results.](ArrayCovariance_code.png)
+When the array is an array of sealed types, JIT knows there won’t be any covariance involved when sealed types are used, so it skips covariance checks. This improves performance with arrays.
 
-![Figure: Performance results show arrays with sealed types show improved performance compared to arrays with non-sealed types.](ArrayCovariance_PerfResults.png)
+![Figure: Array covariance - sealed Vs non-sealed. See the next figure for performance results](ArrayCovariance_code.png)
+
+![Figure: Performance results show arrays with sealed types show improved performance compared to arrays with non-sealed types](ArrayCovariance_PerfResults.png)
 
 ### Skip hierarchy checks of inheritance in runtime for is/as cast operations
 
-During a cast operation, JIT needs to know the type of the object at runtime. When casting to a non-sealed type, the runtime must check all the types in the inheritance hierarchy, which can be time consuming. When casting to a sealed type, the runtime only checks the type of the object. Hence the performance gain.
+During a cast operation, JIT needs to know the type of the object at runtime. When casting to a non-sealed type, the runtime must check all the types in the inheritance hierarchy, which can be time consuming. 
+
+When casting to a sealed type, the runtime only checks the type of the object. Hence the performance gain.
 
-![Figure: Casting sealed Vs non-sealed. See the next figure for performance results.](Casting_code.png)
+![Figure: Casting sealed Vs non-sealed. See the next figure for performance results](Casting_code.png)
 
-![Figure: Performance results show casting of sealed has improved performance compared to non-sealed.](Casting_PerfResult.png)
+![Figure: Performance results show casting of sealed has improved performance compared to non-sealed](Casting_PerfResult.png)