Incorrect documentation for Tree#walk

[JC3]

The documentation for Tree#walk at https://www.nodegit.org/api/tree/#walk states that "entry" sends a Tree and "end" sends Array<Tree>.

This is not correct. "entry" actually appears to send TreeEntry, and "end" actually appears to send Array<TreeEntry>:

• console.log of the event parameters confirms they are TreeEntry
• The sent entity does not have any of the members that Tree has.

(As a side note, it would be super helpful if a note about not forgetting to call start() was also in this documentation, as well as a description of what the actual sent TreeEntrys are -- it's currently only in the tree walking example code.)