Inject language or reference is not remembered/saved after restart

It is expected result. By default, the IDE injects a language temporarily. It means that if you delete the embedded element or restart the IDE, the injection will be lost as well.

Please see https://www.jetbrains.com/help/idea/using-language-injections.html#language_annotation on how to make it permanent.

Thank you for the response, but I need to remember the injection inside of a cucumber .feature file. Example:

And pass headers to request
"""
{
  "Accept": "application/json",
  "Content-type": "application/json"
}
"""

Is this possible?

You can try using it in the following way:

"""json
{
  "Accept": "application/json",
  "Content-type": "application/json"
}
"""