Add link titles for all links in the class reference

This makes them display in a nicer way in the editor help.
(The title will display instead of the full URL.)

doc/classes/SoftBody3D.xml

@@ -7,7 +7,7 @@
 		A deformable physics body. Used to create elastic or deformable objects such as cloth, rubber, or other flexible materials.
 	</description>
 	<tutorials>
-		<link>https://docs.godotengine.org/en/latest/tutorials/physics/soft_body.html</link>
+		<link title="SoftBody">https://docs.godotengine.org/en/latest/tutorials/physics/soft_body.html</link>
 	</tutorials>
 	<methods>
 		<method name="add_collision_exception_with">