Closes #ISSUE
Adds a visual indicator to the `Arguments` column of the keymap table to
help distinguish between actions that don't take arguments, and actions
that take arguments but none were provided.
Currently, the `<no arguments>` indicator is rendered only in the latter
case, when no arguments are provided to an action that could take
arguments, as the inverse results in almost every row containing the
indicator which is quite noisy.
Release Notes:
- N/A *or* Added/Fixed/Improved ...