* Translation: Update binary_tree.md
simplified some parts while others added a few words to make it clearer
* translation: Update binary_tree.md
edited most of the stuff that QiLOL has suggestion, again thanks QiLOL for the review
* translation: Update binary_tree.md
changed to simpler words instead.
Did not update the 2nd part, as I'm waiting for Khrahets to make the final decision