Fix `inspector<T[N]>`.

[1uc]

Adds prepare and data (non-cost) methods to inspector<T[N]>. This is needed to serialize a int a[][] = {{1, 2, 3}, {4, 5, 6}}; without the read(T*, ...) overload.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (3ea8154) 85.94% compared to head (ceb24b6) 85.94%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #929 +/- ## ======================================= Coverage 85.94% 85.94% ======================================= Files 89 89 Lines 5862 5862 ======================================= Hits 5038 5038 Misses 824 824 ```

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