fix(typeahead): Fix crash on Firefox and `contenteditable` input (#2057)
fix(typeahead): Fix crash on Firefox and `contenteditable` input (#2057)

When using the typeahead directive on a `contenteditable` input, crashes
can happen on Firefox:

    TypeError
    n.target.innerText is undefined

According to many sources [1] [2] [3], `innerText` should only be used
on old browsers where `textContent` in not defined (e.g. Internet
Explorer). On newer browsers that abide by standards, `textContent` is
the right property to use to avoid problems.

[1]: https://stackoverflow.com/a/22990890
[2]: https://teamtreehouse.com/community/firefox-innertext-undefined-teachers-note
[3]: https://developer.mozilla.org/en-US/docs/Web/API/Node/textContent
Le0Michine/ng2-bootstrap,valor-software/ngx-bootstrap,Le0Michine/ng2-bootstrap,valor-software/ngx-bootstrap,valor-software/ngx-bootstrap,valor-software/ngx-bootstrap,valor-software/ng2-bootstrap,valor-software/ng2-bootstrap