Update README.md

Typo =)

Author: bboyho

README.md

@@ -26,4 +26,4 @@ The SparkFun Toolkit is available as a *Beta* release, with the intent of testin
 
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-|[Bus Implementation](docs/ar_ibus.md) | The architecture and use of the Tookkit Communication Bus Interface
+|[Bus Implementation](docs/ar_ibus.md) | The architecture and use of the Toolkit Communication Bus Interface