Fix broken intro link

Author: PaulZC

README.md

@@ -52,7 +52,7 @@ Thanks:
 Documentation
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-* **[RTK Product Manual](https://docs.sparkfun.com/SparkFun_RTK_Firmware/intro/)** - A detail guide describing all the various software features of the RTK product line.   Essentially it is a manual for the firmware in this repository.
+* **[RTK Product Manual](https://docs.sparkfun.com/SparkFun_RTK_Firmware/)** - A detail guide describing all the various software features of the RTK product line.   Essentially it is a manual for the firmware in this repository.
 * **[RTK Facet L-Band Hookup Guide](https://learn.sparkfun.com/tutorials/sparkfun-rtk-facet-l-band-hookup-guide)** - Hookup guide for the SparkFun RTK Facet L-Band.
 * **[RTK Facet Hookup Guide](https://learn.sparkfun.com/tutorials/sparkfun-rtk-facet-hookup-guide)** - Hookup guide for the SparkFun RTK Facet.
 * **[RTK Express Hookup Guide](https://learn.sparkfun.com/tutorials/sparkfun-rtk-express-hookup-guide)** - Hookup guide for the SparkFun RTK Express and Express Plus.