BUG: 411508
## ISO C ++
* Add folding for digraphs `<%`, `%>`, `<:` and `:>`, which are equivalent to `{`, `}`, `[` and `]`.
* Fix the highlight of `%:` in preprocessor, for example, `%:include <some>`.
## C
* Add folding for digraphs `<%` and `%>`, which are equivalent to `{` and `}`.
* Add `%:` equivalent to `#` in preprocessor.
Trigraphs were removed in C++17 and are supported in C (if activated in the compiler), but are almost obsolete. That's why I decided not to add them. Although if you wish I can add folding to `??<` and `??>`, which are equivalent to `{` and `}`.
**More:**
* https://en.wikipedia.org/wiki/Digraphs_and_trigraphs#C