I wrote a browser plugin in Go (using gopherjs) that will humanize words like it, it's, and its when you press a hotkey while the cursor is on them. It will randomly pick between his/her or her/his. I'd put it on github if you like, but it would need a bit of cleaning up and work first.

It is certainly painful to read, particularly when the author is actually talking about a real person, who presumably is either a "her" or a "him."