You can see its popularity rising using Google Trends right at the time the leaks occurred which was October 2016:

https://trends. google.com/trends/explore?date=all&q=fake%20news (just copy URL to search bar and delete space between 'trends and 'google', this URL is banned here so I had to add it this way)

One of the very first alternative media sites to cover this (besides 4Chan) was News Punch:

https://newspunch.com/wikileaks-pedophile-code-words-podesta/

And the very beginnings of Pizza.Gate being reported with the introduction of the term 'fake news' in the media was documented by others:

https://truthearth.org/2016/11/22/pizzagate-plus-current-eventsintel-compilation/

https://truthearth.org/2017/10/17/where-did-the-term-fake-news-originate/

So whenever you see the term 'fake news', you know where and when it was weaponized against truthers.

Here's a Positive Uplifting Video if You Feel Guided to See it