Core: Format Placement::toString() and fix const correctness

src/Base/Placement.cpp

@@ -212,21 +212,17 @@ Placement Placement::sclerp(const Placement& p0, const Placement& p1, double t,
     return p0 * trf.pow(t, shorten);
 }
 
-std::string Placement::toString()
+std::string Placement::toString() const
 {
     Base::Vector3d pos = getPosition();
     Base::Rotation rot = getRotation();
 
     Base::Vector3d axis;
-    double angle;
+    double angle {};
     rot.getRawValue(axis, angle);
 
+    // clang-format off
     return fmt::format("position ({:.1f}, {:.1f}, {:.1f}), axis ({:.1f}, {:.1f}, {:.1f}), angle {:.1f}\n",
-                       pos.x,
-                       pos.y,
-                       pos.z,
-                       axis.x,
-                       axis.y,
-                       axis.z,
-                       angle);
+                       pos.x, pos.y, pos.z, axis.x, axis.y, axis.z, angle);
+    // clang-format on
 }

src/Base/Placement.h

@@ -108,7 +108,7 @@ public:
     sclerp(const Placement& p0, const Placement& p1, double t, bool shorten = true);
 
     /// Returns string representation of the placement, useful for debugging
-    std::string toString();
+    std::string toString() const;
 
 private:
     Vector3<double> _pos;