params: ensure short description is only a single line

So a UI can display it properly

src/drivers/rpm/pcf8583/parameters.c

@@ -33,7 +33,8 @@
 
 /**
  * PCF8583 rotorfreq (i2c) pool interval
- * How often the sensor is readout.
+ *
+ * Determines how often the sensor is read out.
  *
  * @reboot_required true
  * @group Sensors

src/drivers/telemetry/iridiumsbd/iridiumsbd_params.c

@@ -20,7 +20,8 @@ PARAM_DEFINE_INT32(ISBD_READ_INT, 0);
 PARAM_DEFINE_INT32(ISBD_SBD_TIMEOUT, 60);
 
 /**
- * Time [ms] the Iridium driver will wait for additional mavlink messages to combine them into one SBD message
+ * Time the Iridium driver will wait for additional mavlink messages to combine them into one SBD message
+ *
  * Value 0 turns the functionality off
  *
  * @unit ms