[wpilib] Add link to MotorSafety article (#4720)

wpilibc/src/main/native/cpp/MotorSafety.cpp

@@ -159,7 +159,9 @@ void MotorSafety::Check() {
   }
 
   if (stopTime < Timer::GetFPGATimestamp()) {
-    FRC_ReportError(err::Timeout, "{}... Output not updated often enough",
+    FRC_ReportError(err::Timeout,
+                    "{}... Output not updated often enough. See "
+                    "https://docs.wpilib.org/motorsafety for more information.",
                     GetDescription());
 
     try {

wpilibj/src/main/java/edu/wpi/first/wpilibj/MotorSafety.java

@@ -96,7 +96,10 @@ public abstract class MotorSafety {
     }
 
     if (stopTime < Timer.getFPGATimestamp()) {
-      DriverStation.reportError(getDescription() + "... Output not updated often enough.", false);
+      DriverStation.reportError(
+          getDescription()
+              + "... Output not updated often enough. See https://docs.wpilib.org/motorsafety for more information.",
+          false);
 
       stopMotor();
     }