Draws four panels of convergence diagnostics for an iterated INLA method estimation

## Examples

```
if (FALSE) {
fit <- bru(...)
bru_convergence_plot(fit)
}
```

Draws four panels of convergence diagnostics for an iterated INLA method estimation

```
if (FALSE) {
fit <- bru(...)
bru_convergence_plot(fit)
}
```