**IMPORTANT!** Before picking this up for the sprint, arrange a task breakdown for this with @Sarai-WMDE, as the work here can be parallelized
**States**
List of the states that the component should display, mapping the specs:
[] Disabled
[] ReadOnly (prefilled)
[] Loading
[] Error
[] Warning
**Notes:**
* All states should be displayed in Storybook on the "All" page.
* This is development happening in Wikit, not the Mismatch Finder anymore.
* Pulled originally from https://phabricator.wikimedia.org/T287568
* Loading state: The loading state of the component needs to be implemented in this first iteration due to product needs (displaying that the user input is being processed). 1) The assumption is that the `loading` state can be developed as a `prop` (like `error` or `disabled`). 2) The inline loading bar is a small, separate component (most likely a mixin): should we implement both elements (text area + inline loading bar) as part of the same task?
* The text area presents a "read only" state while loading. While in read only, only the background color of the input changes, and the entered value can be selected and copied, but not modified.
* The inline loader tokens are created according to the naming convention and used to style it (a draft is available in this PR: https://github.com/wmde/wikit/pull/458)