Examples 119 and 120 don't seem right

[VladimirAlexiev]

(related to #397)

• Example 119 https://w3c.github.io/json-ld-syntax/#example-indexing-graph-data-in-json-ld
• Example 120 https://w3c.github.io/json-ld-syntax/#example-indexing-graphs-using-none-for-no-index

Are supposed to demonstrate "default graph referencing multiple named graphs using an index map".

• But both graphs end up being anonymous.
  • Especially Example 120 is supposed to show the difference between en and @none but both graphs are anonymous
• Also, both examples show a warning (or error?) in the playground. Maybe the JSON schema in the playground is not up to date?