Caused by: org.infinispan.protostream.DescriptorParserException: IPROTO000013: Error while parsing 'SimpleEntitySchema.proto': Error: 2,1: illegal character: 

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Hello,
I saw simillar issue #196 where it was fixed, however, there is a simillar issue, where other symbols aren't covered with provided solution in #196.

*Used Kotlin and JDK 17, and this dependencies:*
```
implementation("org.infinispan.protostream:protostream:5.0.12.Final")
compileOnly("org.infinispan.protostream:protostream-processor:5.0.12.Final")
kapt("org.infinispan.protostream:protostream-processor:5.0.12.Final")
```

For example.
**SImpleEntity**
```
import org.infinispan.protostream.annotations.ProtoField

data class SimpleEntity(
@get:ProtoField(number = 1) var name: String? = null,
@get:ProtoField(number = 2) var message: String? = null
)
```

**SimpleEntitySchema**
```
@ProtoSchema(includeClasses = [SimpleEntity::class], schemaPackageName = "proto")
interface SimpleEntitySchema : GeneratedSchema
```

**Generated SimpleEntitySchemaImpl.java**
```
public class SimpleEntitySchemaImpl implements proto.SimpleEntitySchema {

private static final String PROTO_SCHEMA = """
// File name: SimpleEntitySchema.proto
// Generated from : SimpleEntitySchema.proto
syntax = "proto2";
package proto;

/**
* @Metadata(mv={1, 9, 0}, k=1, xi=48, d1={"\u0000\"\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0002\b\f\n\u0002\u0010\u000b\n\u0002\b\u0002\n\u0002\u0010\b\n\u0002\b\u0002\b\u0086\b\u0018\u00002\u00020\u0001B\u001d\u0012\n\b\u0002\u0010\u0002\u001a\u0004\u0018\u00010\u0003\u0012\n\b\u0002\u0010\u0004\u001a\u0004\u0018\u00010\u0003\u00a2\u0006\u0002\u0010\u0005J\u000b\u0010\f\u001a\u0004\u0018\u00010\u0003H\u00c6\u0003J\u000b\u0010\r\u001a\u0004\u0018\u00010\u0003H\u00c6\u0003J!\u0010\u000e\u001a\u00020\u00002\n\b\u0002\u0010\u0002\u001a\u0004\u0018\u00010\u00032\n\b\u0002\u0010\u0004\u001a\u0004\u0018\u00010\u0003H\u00c6\u0001J\u0013\u0010\u000f\u001a\u00020\u00102\b\u0010\u0011\u001a\u0004\u0018\u00010\u0001H\u00d6\u0003J\t\u0010\u0012\u001a\u00020\u0013H\u00d6\u0001J\t\u0010\u0014\u001a\u00020\u0003H\u00d6\u0001R\u001e\u0010\u0004\u001a\u0004\u0018\u00010\u00038\u0007X\u0086\u000e\u00a2\u0006\u000e\n\u0000\u001a\u0004\b\u0006\u0010\u0007\"\u0004\b\b\u0010\tR\u001e\u0010\u0002\u001a\u0004\u0018\u00010\u00038\u0007X\u0086\u000e\u00a2\u0006\u000e\n\u0000\u001a\u0004\b\n\u0010\u0007\"\u0004\b\u000b\u0010\t\u00a8\u0006\u0015"}, d2={"Lproto/SimpleEntity;", "", "name", "", "message", "(Ljava/lang/String;Ljava/lang/String;)V", "getMessage", "()Ljava/lang/String;", "setMessage", "(Ljava/lang/String;)V", "getName", "setName", "component1", "component2", "copy", "equals", "", "other", "hashCode", "", "toString", "api-quarkus"})
*/
message SimpleEntity {

/**
* @Nullable
*/
optional string name = 1;

/**
* @Nullable
*/
optional string message = 2;
}

""";

@Override
public String getProtoFileName() { return "SimpleEntitySchema.proto"; }

@Override
public String getProtoFile() { return PROTO_SCHEMA; }

@Override
public void registerSchema(org.infinispan.protostream.SerializationContext serCtx) {
serCtx.registerProtoFiles(org.infinispan.protostream.FileDescriptorSource.fromString(getProtoFileName(), getProtoFile()));
}

@Override
public void registerMarshallers(org.infinispan.protostream.SerializationContext serCtx) {
serCtx.registerMarshaller(new proto.SimpleEntity$___Marshaller_4f3e7dce92faed34c3d7bb610b4b830d4b6a80ba2cbe67131793b5b4936fce4a());
}
}
```

**I am using Embedded Infinispan cache with Quarkus, if it does matter.**
```
@ApplicationScoped
class EmbeddedCache {

private val cacheManager = DefaultCacheManager(
GlobalConfigurationBuilder().clusteredDefault().serialization().addContextInitializer(
SimpleEntitySchemaImpl()
).build()
).apply {
defineConfiguration(
"embedded-cache", ConfigurationBuilder().encoding().mediaType(MediaType.APPLICATION_PROTOSTREAM).build()
)
}

private val keyCounter = AtomicLong(1)

private val cache: Cache = cacheManager.getCache("embedded-cache")

fun put(entity: SimpleEntity): String {
val generatedKey = keyCounter.getAndIncrement()
cache.put(generatedKey, entity)
return "Successfully created new entity: $generatedKey | ${entity.name}"
}

fun get(key: Long): SimpleEntity? = cache[key]

fun getAllEntities(): Map = cache

fun updateEntity(key: Long, entity: SimpleEntity): String {
if (cache[key] != null) {
cache.put(key, entity)
return "Successfully updated entity: $key | ${entity.name}"
}
return "No entity with this id: $key"
}

fun remove(key: Long): String {
if (cache[key] != null) {
cache.remove(key)
return "Successfully removed entity: $key"
}
return "No entity with this id: $key"
}

@PreDestroy
fun destroy() {
cacheManager.stop()
}
}
```

**Exception StackTrace**
```
Caused by: org.infinispan.protostream.DescriptorParserException: IPROTO000013: Error while parsing 'SimpleEntitySchema.proto': Error: 2,1: illegal character: 
at org.infinispan.protostream.impl.parser.ProtostreamProtoParser.parse(ProtostreamProtoParser.java:53)
at org.infinispan.protostream.impl.SerializationContextImpl.registerProtoFiles(SerializationContextImpl.java:105)
```

If i remove `d1` values from `Metadata` annotation or write `SimpleEntity` and `SimpleEntitySchema` in `Java`, everything works **fine**, as it should.

Reproduce the Kotlin/JDK 17 case using the generated SimpleEntitySchemaImpl.java and start at ProtostreamProtoParser.java:53, following registration through SerializationContextImpl.registerProtoFiles. Compare the generated metadata-containing schema with the Java case and issue #196. Done means the generated Kotlin schema registers without the illegal-character exception while retaining its metadata.

Written by the indexing model from the issue text.