FIR LT: add syntax error reporting to LT2Fir

use it in the new pipeline

analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/rendererrs/FirDiagnosticToKtDiagnosticConverterRenderer.kt

@@ -69,6 +69,7 @@ object FirDiagnosticToKtDiagnosticConverterRenderer : AbstractDiagnosticsDataCla
 
     override val defaultImports = listOf(
         "org.jetbrains.kotlin.diagnostics.KtPsiDiagnostic",
+        "org.jetbrains.kotlin.fir.builder.FirSyntaxErrors",
         "org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors",
         "org.jetbrains.kotlin.fir.analysis.diagnostics.jvm.FirJvmErrors",
     )

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.KtPsiSourceElement
 import org.jetbrains.kotlin.diagnostics.KtPsiDiagnostic
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.jvm.FirJvmErrors
+import org.jetbrains.kotlin.fir.builder.FirSyntaxErrors
 import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
@@ -93,12 +94,6 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
-    add(FirErrors.SYNTAX) { firDiagnostic ->
-        SyntaxImpl(
-            firDiagnostic as KtPsiDiagnostic,
-            token,
-        )
-    }
     add(FirErrors.OTHER_ERROR) { firDiagnostic ->
         OtherErrorImpl(
             firDiagnostic as KtPsiDiagnostic,

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -102,10 +102,6 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val error: String
     }
 
-    abstract class Syntax : KtFirDiagnostic<PsiElement>() {
-        override val diagnosticClass get() = Syntax::class
-    }
-
     abstract class OtherError : KtFirDiagnostic<PsiElement>() {
         override val diagnosticClass get() = OtherError::class
     }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -105,11 +105,6 @@ internal class NewInferenceErrorImpl(
     override val token: ValidityToken,
 ) : KtFirDiagnostic.NewInferenceError(), KtAbstractFirDiagnostic<PsiElement>
 
-internal class SyntaxImpl(
-    override val firDiagnostic: KtPsiDiagnostic,
-    override val token: ValidityToken,
-) : KtFirDiagnostic.Syntax(), KtAbstractFirDiagnostic<PsiElement>
-
 internal class OtherErrorImpl(
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: ValidityToken,