[wpilib] MechanismLigament2d: Add getters for color and line weight (#3947)

Also add missing locking in C++.

wpilibc/src/main/native/include/frc/smartdashboard/MechanismLigament2d.h

@@ -34,7 +34,14 @@ class MechanismLigament2d : public MechanismObject2d {
    *
    * @param color the color of the line
    */
-  void SetColor(const frc::Color8Bit& color);
+  void SetColor(const Color8Bit& color);
+
+  /**
+   * Get the ligament color.
+   *
+   * @return the color of the line
+   */
+  Color8Bit GetColor();
 
   /**
    * Set the ligament's length.
@@ -71,6 +78,13 @@ class MechanismLigament2d : public MechanismObject2d {
    */
   void SetLineWeight(double lineWidth);
 
+  /**
+   * Get the line thickness.
+   *
+   * @return the line thickness
+   */
+  double GetLineWeight();
+
  protected:
   void UpdateEntries(std::shared_ptr<nt::NetworkTable> table) override;