tex-l3kernel{,-doc}: update to 2022

## [2022-08-23]
### Added
- Shortened range of chars which are left unchanged when converted to
  strings with `\str_(g)set_convert:Nnnn`.
- `\color_if_exist:n(TF)`
- Support for case changing Vietnamese characters with 8-bit engines
- Parsing of `cmy`, `tHsb` and `&spot` color models to support data exchange with
  `xcolor`
### Changed
- Replace `LaTeX3` in message text by `LaTeX`

## [2022-08-05]
### Added
- Support for case changing Croatian diagraph with 8-bit engines
- Support accent removal when uppercasing Greek with 8-bit engines
- Function `\sys_ensure_backend:`
### Fixed
- Behavior of `\color_math:nn` in alignments
- Expansion of text containing unterminated `\romannumeral` primitives

## [2022-07-14]
### Changed
- Improved approach to `\text_case_switch:nnnn` expansion

## [2022-07-15]
### Fixed
- Correct argument order in `\text_case_switch:nnnn`

## [2022-07-04]
### Added
- `\text_declare_case_equivalent:Nn`, `\text_case_switch:nnnn` and
  related mechanism to allow specialisation of case changing output
  for selected commands

(markd)