Documentation: Better search

## Expected Behavior
If a user is not sure where in the documentation the headers (h1, h2, h3, etc) are located - they search "H3" (or similar tag), for example, in the documentation search box and would like to quickly see the results.

## Current Behavior
Right now, doing that yields no results, so I have to click through every single topic until I find the right one (`Elements`!)

## Possible Solution
Some sort of full-text or partial-full-text search would be much better I think. I know there are potential issues with this, for example what if I search the word `Item`? `Item` is used extensively in the example code so there would be way too many matches to be helpful.