Remove an unused check
Remove an unused check

Directives always get instantiated with a valueRange so it's never
going to be null.

Signed-off-by: Remy Suen <553f7e7fc51e9ff47ae89d5a0ebd06651241b998@gmail.com>

rcjsuen/dockerfile-language-server-nodejs,rcjsuen/dockerfile-language-server-nodejs