For multi-word nouns, the word boundary is detected incorrectly

If the noun for a resource has multiple words and contains a word with only an initial uppercase letter and digits, for example `ServiceV2Config`, the word boundary will be detected as `Service` + `V2config` as two separate words rather than three separate words `Service` + `V2` + `Config`. This causes the linter to flag methods such as

```
rpc UpdateServiceV2Config(UpdateServiceV2ConfigRequest) returns (ServiceV2Config) {
option (google.api.http) = {
patch: "/v1/{service_v2_config.name=accounts/*/serviceV2Configs/*}"
body: "service_v2_config"
};
option (google.api.method_signature) = "service_v2_config,update_mask";
}
```

Because the linter thinks that the correct name is `service_v2config`.