[wpilib] Rename LinearSystemSim's ResetState() to SetState() (#2750)

This makes it more consistent with all other simulation classes,
including the differential drive simulation class.

wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/LinearSystemSim.java

@@ -121,7 +121,12 @@ public class LinearSystemSim<States extends Num, Inputs extends Num,
     return m_y.get(row, 0);
   }
 
-  public void resetState(Matrix<States, N1> state) {
+  /**
+   * Sets the system state.
+   *
+   * @param state The state.
+   */
+  public void setState(Matrix<States, N1> state) {
     m_x = state;
   }