Improved menu title display when title is too long

[JoJoJotarou]

It might be a good idea to hide a headline when it's too long. If you agree~

before：

after:

[RamiSJ12]

Super duper inovation, follow you

[alex-shpak]

Hi! Thanks for the PR. I was considering ellipsizing titles in menu, but decided to leave it for user to customize. in _custom.scss

Unfortunately presented solution is webkit specific, would be nice to have generic soution.

[salzig]

according to https://caniuse.com/css-line-clamp it should work in all modern browsers.