* Use new macro syntax for encoding sequences of keys
* Make convenience helpers for common test pattern
* Use indoc for inline indented raw strings
* Add feature flag for integration testing to disable rendering

When a new View of a Document is created, a default cursor of 0, 0 is
created, and it does not get normalized to a single width cursor until
at least one movement of the cursor happens. This appears to have no
practical negative effect that I could find, but it makes tests difficult
to work with, since the initial selection is not what you expect it to be.

This changes the initial selection of a new View to be the width of the
first grapheme in the text.

Use the Application's main event loop to allow LSP, file writes, etc

During write-quit, if the file fails to be written for any reason, helix
will still quit without saving the changes. This fixes this behavior by
introducing fallibility to the asynchronous job queues. This will also
benefit all contexts which may depend on these job queues.

Fixes helix-editor#1575