Similar issues filed: #4181, #5087, #7051, #12142.

While editing a post in Gutenberg, I couldn't figure out how to indent list items by the keyboard which is a habit of mine (and I'd argue many others editors as well).

Describe the bug
No keyboard shortcuts display for the list block.

Mentioned in #7051 but that issue is not dedicated to this, I decided to make a new issue for this; close if this is too explicit.

To Reproduce
without looking on a separate page of documentation, right now:

1. add a new page or edit a page in Gutenberg
2. add a list block,
3. try to indent a list item using only the keyboard; did ya have to look at the docs :D.

Expected behavior
Personally, the expected action to indent an item in a list block would be done by issuing 'TAB' but that has been decided against for accessibility reasons
That the default behavior isn't used stresses the utility of having the keyboard shortcuts for list actions (outdenting, indenting) available.

Screenshots
see https://user-images.githubusercontent.com/1682452/40778281-f1054ca2-64d0-11e8-953f-704ef1e5ba1d.png

Additional context

• (Update: still present in WordPress 5.0.2)
  (Issue made on CPL time)