crd docs: Field names mentioned in docs are snake case whereas our field names are lower camel

### What problem are you facing?

Since we scrape TF registry for documentation, some fields refer to others with their snake case field name like [this one](https://marketplace.upbound.io/providers/upbound/provider-aws/v0.8.0/resources/rds.aws.upbound.io/Cluster/v1beta1#doc:spec-forProvider-dbInstanceParameterGroupName) where the description of `dbInstanceParameterGroupName` includes the following sentence:
```
The db_instance_parameter_group_name parameter is only valid in combination with the allow_major_version_upgrade parameter.
```

### How could Official Providers help solve your problem?

We can scan and replace them with their Crossplane counterparts.