Insert a space after certain marks on left arrow key press so they don't trap the cursor.

[b-kelly]

This is a meta-entry to track items such as #31 and #49.

Is your feature request related to a problem? Please describe.

Specific marks (e.g. code_inline and kbd) appear to "trap" the cursor, even though their behavior is consistent to other marks (e.g. italics or bold). The common behavior is that activating a mark (e.g. ctrl+i for italics) will keep the cursor in that typing mode until it is again deactivated. You can see this behavior in other editors as well. However, some marks that seem like standalone chunks (kbd, code_inline) trigger an expectation in users that they can "leave" these chunks at will by manually moving the cursor with the arrow keys. You can see this behavior in Slack's code formatting.

Describe the solution you'd like

For a small subset of marks, when the user uses the right arrow key to move outside of it and there is no other content to the right of it, disable the mark and add a space. This is consistent with the behavior seen in Slack.

Describe alternatives you've considered

We could just not do anything and consider all marks to behave the same. However, since we have received independent user reports about this behavior, this would likely not be the most UX friendly option.