Merge topic 'preset-schema-refactor'

3373abf901 presets: Require valid CMake cache variable type in schema
c5862fee8f Help/presets: Improve formatting of some references
eee0bd2f6a presets: Factor out additional fields in schema
a9ad31820b presets: Refactor JSON schema
4e1dfc5194 Tests: Print concise error in JSON schema validation

Acked-by: Kitware Robot <[email protected]>
Tested-by: buildbot <[email protected]>
Merge-request: !11591