Provide help text on Entity Reference widgets if there's no referenceable entity

I think the comments in #4 make more sense and would be easier to achieve than hiding the widget, therefore marking this as a feature.

Please review.

The Needs Review Queue Bot → tested this issue. It fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

This does not mean that the patch needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

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Will need test coverage

Gauravvvv → made their first commit to this issue’s fork.

Provided some feedback, we still need tests and we haven't got any changes to the autocomplete widget which seems like this issue is targeted at from the IS.

Updating IS wording also.

omkar.podey → made their first commit to this issue’s fork.