OCR instructions: add trailing spaces in examples

See [forum
post](http://forum.exercism.org/t/rewrite-instructions-for-ocr-numbers/19894/15)

Author: IsaacG

exercises/ocr-numbers/instructions.md

@@ -28,16 +28,16 @@ The following input (without the comments) is converted to `"1234567890"`.
 The following input is converted to `"123,456,789"`.
 
 ```text
-    _  _
+    _  _ 
   | _| _|
   ||_  _|
-
-    _  _
-|_||_ |_
+         
+    _  _ 
+|_||_ |_ 
   | _||_|
-
- _  _  _
+         
+ _  _  _ 
   ||_||_|
   ||_| _|
-
+         
 ```