prefixItems with the same minItems and maxItems value should generate tuples

For example, if we want a list of lat, lon coordinates, this:
```yaml
type: array
items:
type: array
minItems: 2
maxItems: 2
prefixItems:
- number
- number
```
should generate:
```
[number, number][];
```
rather than the current:
```
any[][]
```

----

For now the closest we seem to be able to get is:
```yaml
type: array
items:
type: array
items:
type: number
```
generating:
```
number[][]
```