Fix readme

examples/hsitrim/README.md

 This example demonstrates the HSITRIM feature of the High Speed Internal clock.  Upon startup, the HSICAL value
-is loaded into the RCC_CTLR register and HSICAL is loaded with the value 16 i(0b10000).  This example uses the MCO
+is loaded into the RCC_CTLR register and HSICAL is loaded with the value 16 (0b10000).  This example uses the MCO
 feature to route the HSI clock signal to an external pin (PC4) and to allow the HSITRIM value to be varied by
 interactive commands over the serial port.