## Documentation

- Use mathjax for now (#1538).

## Testing

- Fold test-bonpow into test-centrality.

- Fold `closeness()`'s tests into test-centrality.

- Fold `edge_betweenness()`'s tests into test-centrality.

- Fold `betweenness()`'s tests into test-centrality.R.

- Fold `hits_scores()`'s tests into test-centrality.

- Add tests for as_adjacency_matrix() in test-conversion (#1519).