README: Add stm32f730-lpc

Author: maximeborges

README.md

@@ -28,7 +28,7 @@ If no microcontroller is specified, the crate will not compile.
 * `stm32f722`
 * `stm32f723`
 * `stm32f730`
-* `stm32f730-lpc` ("low pin count" variant
+* `stm32f730-lpc` ("low pin count" variant)
 * `stm32f732`
 * `stm32f733`
 * `stm32f745`