[hal] Expose more FPGA functionality (#6942)

- function to reset user rail fault counters
- function to get comms disable count
- correct docs for user rail count functions

hal/src/main/native/cpp/jni/HAL.cpp

@@ -154,6 +154,21 @@ Java_edu_wpi_first_hal_HAL_getBrownedOut
   return val;
 }
 
+/*
+ * Class:     edu_wpi_first_hal_HAL
+ * Method:    getCommsDisableCount
+ * Signature: ()I
+ */
+JNIEXPORT jint JNICALL
+Java_edu_wpi_first_hal_HAL_getCommsDisableCount
+  (JNIEnv* env, jclass)
+{
+  int32_t status = 0;
+  int32_t val = HAL_GetCommsDisableCount(&status);
+  CheckStatus(env, status);
+  return val;
+}
+
 /*
  * Class:     edu_wpi_first_hal_HAL
  * Method:    getRSLState