fix: doNotSuggest for property and value completion

[p-spacek]

What does this PR do?

RedHat PR: redhat-developer#911

exclude doNotSuggest schema from autocompletion
doNotSuggest was already there but implemented only for the simple object properties.
This PR uses doNotSuggest also for other scenarios: anyOf, values

"anyOf":[
  {
     "$ref": "schema1",
     "doNotSuggest": true
   },
  {
     "$ref": "schema2",
   }
]

Is it tested? How?

adds unit tests