doc: finishing touches api review for `keyCopy()`, restyled fixes
- [x] better describe flags (|)
-
@copydoc for invariants?
```
- [x] Function name should be clear and unambiguous
- [ ] Abbreviations used in parameter names must be defined in the
[Glossary](/doc/help/elektra-glossary.md)
- - [ ] add dest to glossary - maybe rename dest to destination?
+ - [x] add dest to glossary - maybe rename dest to destination?
- [x] Parameter names should neither be too long, nor too short
- [x] Parameter names should be clear and unambiguous
- [x] Function name has the appropriate prefix
- [x] Signature in kdb.h.in has same order as Doxygen docu
- [ ] No functions with similar purpose exist
- - [ ] keyCopyAllMeta
+ - [x] keyCopyAllMeta
### Memory Management
- [x] Function is easily extensible, e.g., with flags
- [ ] Documentation does not impose limits, that would hinder further extensions
- - [ ] KEY_CP_ALL equivalent to KEY_CP_NAME | KEY_CP_VALUE | KEY_CP_META
+ - [x] KEY_CP_ALL equivalent to KEY_CP_NAME | KEY_CP_VALUE | KEY_CP_META
### Tests
https://doc.libelektra.org/coverage/master/debian-buster-full/src/libs/elektra/key.c.gcov.html
- [ ] All possible error states are covered by tests and documented
- [ ] All possible enum values are covered by tests
- - [ ] use flags other than KEY_CP_ALL
+ - [x] use flags other than KEY_CP_ALL
- [ ] No inconsistencies between tests and documentation
- [ ] Functions should have no side effects (idempotency)
