changed the properties of avl trees (#27322)
changed the properties of avl trees (#27322)

Changed the property that said that the AVL tree can have zero or more child nodes to avl tree can have zero, one or two child nodes.
FreeCodeCamp/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,jonathanihm/freeCodeCamp,raisedadead/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,jonathanihm/freeCodeCamp,FreeCodeCamp/FreeCodeCamp,raisedadead/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp