- insert(array, index, value): insert before an element (index <= size)
- erase(object, key): remove all members with the key; returns their
number
- erase(array, index): remove an element
- erase(json_pointer): remove the member or element a pointer names
The errors are those of basic_json (type_error.307/309,
out_of_range.401/403/405). A view of an erased value keeps its last value,
and views of other values keep referring to them when elements move.
Tests: the differential test now also inserts and erases members and
elements, directly and through JSON pointers; plus the errors, views
across inserts and erasures, duplicate keys, and large objects.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>