strange symbols in generated code

unmarshalN__DirectiveLocation2ᚕstringᚄ

in generated file i can see strange symbols, does it possible to generate code only with standard symbols ?

my schema:
```
directive @AccountService on FIELD_DEFINITION
type Account {
id: String
parent: String
zone: String
status: AccountStatus
login: String
passw: String
type: AccountType
createdAt: Int
updatedAt: Int
deletedAt: Int
info: AccountInfo
metadata: [Account_MetadataEntry!]
}
enum AccountAddress {
ACCOUNT_ADDRESS_UNSPECIFIED
ACCOUNT_ADDRESS_REGISTRATION
ACCOUNT_ADDRESS_CURRENT
ACCOUNT_ADDRESS_CORPORATE
}
type AccountInfo {
name: String
email: String
id: String
contacts: [Contact!]
addresses: [Address!]
}
enum AccountStatus {
ACCOUNT_STATUS_UNSPECIFIED
ACCOUNT_STATUS_DISABLED
ACCOUNT_STATUS_ENABLED
ACCOUNT_STATUS_BLOCKED
ACCOUNT_STATUS_DELETED
}
enum AccountType {
ACCOUNT_TYPE_UNSPECIFIED
ACCOUNT_TYPE_PRIVATE
ACCOUNT_TYPE_CORPORATE
}
type Account_MetadataEntry {
key: String
value: String
}
type Address {
type: AccountAddress
value: String
}
type Contact {
type: ContactType
value: String
}
enum ContactType {
CONTACT_TYPE_UNSPECIFIED
CONTACT_TYPE_EMAIL
CONTACT_TYPE_PHONE
CONTACT_TYPE_MESSENGER
}
input CreateAccountReqInput {
name: String
}
type ListAccountRsp {
accounts: [Account!]
}
type Mutation {
accountServiceCreateAccount(in: CreateAccountReqInput): Boolean @AccountService
accountServiceUpdateAccount: Boolean @AccountService
accountServiceDeleteAccount: Boolean @AccountService
}
type Query {
accountServiceListAccount: ListAccountRsp @AccountService
accountServiceLookupAccount: Boolean @AccountService
}

```

这个 issue 涉及从 GraphQL schema 生成的 Go 代码中出现 'ᚕ' 之类的奇怪符号。查看 gqlgen 的代码生成过程，可能需要关注负责生成 unmarshaler 或类型名称的 package。首先使用提供的 schema 重现问题，然后检查生成的文件，确认这些符号是从哪里产生的。检查将 GraphQL 类型名称转换为 Go 标识符的逻辑，可能涉及 Unicode 处理。'Done' 表示生成的代码只使用标准 ASCII 或预期的 Go 标识符字符。

由索引模型根据 Issue 内容生成。