This is an attempt to clean up the inconsistent way that keys are
written in various places. These rules require the fewest changes to the
existing text.
Use the "Key name", as defined in remapping.md, which uses
"Some-Modifiers-PascalCaseKey". The "Representation", which uses
"S-M-lowercasekey", is only used for configuration entries.
For key combinations which do not present a popup, just present the keys
one after the other, with no intervening space, like `]p`.
For key combinations which present a popup, separate them with ` + `,
like `Space + f`.
The Ctrl modifier is called Ctrl, not Control.
* Allow keys to be mapped to sequences of commands
* Handle `Sequence` at the start of `Keymap::get`
* Use `"[Multiple commands]"` as command sequence doc
* Add command sequence example to `remapping.md`
* Add convenience/clarity wrapper for Range initialization
* Add keycode parse and display methods
* Add remapping functions and tests
* Implement key remapping
* Add remapping book entry
* Use raw string literal for toml
* Add command constants
* Make command functions private
* Map directly to commands
* Match key parsing/displaying to Kakoune
* Formatting pass
* Update documentation
* Formatting
* Fix example in the book
* Refactor into single config file
* Formatting
* Refactor configuration and add keymap newtype wrappers
* Address first batch of PR comments
* Replace FromStr with custom deserialize
