fix: set autoEscape to true on demo website

[dorobila]

The demo website was crashing when you typed [ into Search terms box.

Had a discussion with bvaughn about setting the autoEscape param to true on highlight-words-core package, but as he said, changing the default value is going to have performance implications for current users.

[sergei-startsev]

@dorobila autoEscape is not enabled by default, so I'd rather provide an option to enable/disable it on the demo to avoid confusion.

[dorobila]

@sergei-startsev sure thing. I'll add the checkbox, but that is still going to break the app if it's unchecked on page load or unchecked and someone types [.

[sergei-startsev]

@dorobila I agree that this case should be handled out of the box, but changing the defaults can be considered a breaking change. There're some plans to refresh the library, so there will be an opportunity to change it in one of major releases.