Distinguish between schema value completion types (e.g. enum and default/example values)

[davidjb]

Currently, the implementation of methods called by JSONCompletion.addSchemaValueCompletions (addEnumValueCompletions, addDefaultValueCompletions and so on) is such that enum and default values (such as examples from a JSON Schema) are indistinguishable because they're conveyed the same way.

From a schema perspective, however, the two are notably different: enums are enforced during validation but default values and examples are not.

Is it possible for these to be distinguished in some manner when generating the completions?