This also fixes a panic when tabbing on a row that contained multi-byte
characters.

Add bracketed paste support

Added settings for common terminal configurations

Add an admin API for counting users with given amounts of activity

Update terminal testing to match new connection model.

Correctly report all keyboard events to the terminal

Document using Redis and launch it in `Procfile`

Illustrate `format_on_save` external command using prettier

This gives us a chance to highlight a real-world scenario that a lot
of our users will want to use, as well as showcasing the special
`{buffer_path}` argument.

Differentiate among tabs with the same name

Terminal test

Tidied up the terminal theme

More intuitive tab ordering

Plugin json enable

Remove requirement for target triple in precompiled binary extension

This commit introduces a new, optional `Item::tab_description` method
that lets implementers define a description for the tab with a certain
`detail`. When two or more tabs match the same description, we will
increase the `detail` until tabs don't match anymore or increasing the
`detail` doesn't disambiguate tabs any further.

As soon as we find a valid `detail` that disambiguates tabs enough, we
will pass it to `Item::tab_content`. In `Editor`, this is implemented by
showing more and more of the path's suffix as `detail` is increased.