bug#27392: 26.0.50; [css-mode] Completion fails after "grid" is typed out

[Dmitry Gutov]

With these buffer contents (with point at |), press C-M-i:

html {
  gri|
}


It completes to "grid". Press C-M-i again: "No match".

Even though css-mode knows about various grid-** properties, it fails to 
suggest them in this situation.

It *does* offer them as completions after "gri" for `company-capf', however.

Same for "border", "animation" and probably others.

It's a problem for company-capf in particular because with 
company-require-match, after you `M-x company-capf', you're not allowed 
to type out the last letter of each respective word.

It's also a problem in discoverability.