`sbm.game()`

was renamed to `sample_sbm()`

to create a more
consistent API.

## Arguments

- n
Number of vertices in the graph.

- pref.matrix
The matrix giving the Bernoulli rates. This is a \(K\times K\) matrix, where \(K\) is the number of groups. The probability of creating an edge between vertices from groups \(i\) and \(j\) is given by element \((i,j)\). For undirected graphs, this matrix must be symmetric.

- block.sizes
Numeric vector giving the number of vertices in each group. The sum of the vector must match the number of vertices.

- directed
Logical scalar, whether to generate a directed graph.

- loops
Logical scalar, whether self-loops are allowed in the graph.