No Markup field mapping for Search_API_Solr

Problem/Motivation

On the field configuration of /admin/config/search/search-api/index/YOUR-INDEX-NAME/fields/add/nojs it says

The following fields cannot be indexed since there is no type mapping for them:
block button (type "field_item:markup")

and lists all markup fields.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes