* Add more symbols to accent_syperscript
* Add all uppercase and lowercase variants to accent_small_caps
* Use ʁ instead of ᴚ in accent_small_caps

* refactor: Better printing for KeyValue in tests

* Fix parsing of escaped characters in macros

The parsing code was bugged with custom macros like `symbol:\abc` and
`symbol:\\abc`.

This was the case for string keys but not for macros or keys with custom
symbols.

It's replaced with a macro containing one key.

Many kind of KeyValues don't need to be wrapped into a Macro to show a
specific symbol. This is especially useful as Macro keys are not
affected by modifiers.
The parser is changed to have a fast-path when a key value is not a
macro.

This is mostly useful for characters that do not fit on a single 16-bit
char.
Shift sequences for 𝕨𝕩𝕗𝕘𝕤 are added for illustration.

Add "macro" keys that behave as if a sequence of keys is typed.

Macro can be added to custom layouts or through the "Add keys to the
keyboard option". The syntax is:

    symbol:key1,key2,..

The symbol cannot contain a : character. 'key1', 'key2', etc.. are:

  - 'String with \' escaping'
    The key will generate the specified string.
  - keyevent:123
    The key will send a keyevent.
  - The name of any special key

Signed-off-by: Jagadeeshan S <jagadeeshan.s@addverb.com>