[FIR] Add description to NO_ELSE_IN_WHEN and fill it for expect enum or sealed declarations

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

@@ -3822,6 +3822,7 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             firDiagnostic.a.map { whenMissingCase ->
                 whenMissingCase
             },
+            firDiagnostic.b,
             firDiagnostic as KtPsiDiagnostic,
             token,
         )

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

@@ -2670,6 +2670,7 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
     interface NoElseInWhen : KtFirDiagnostic<KtWhenExpression> {
         override val diagnosticClass get() = NoElseInWhen::class
         val missingWhenCases: List<WhenMissingCase>
+        val description: String
     }
 
     interface NonExhaustiveWhenStatement : KtFirDiagnostic<KtWhenExpression> {

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

@@ -3217,6 +3217,7 @@ internal class ExpectedConditionImpl(
 
 internal class NoElseInWhenImpl(
     override val missingWhenCases: List<WhenMissingCase>,
+    override val description: String,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtWhenExpression>(firDiagnostic, token), KtFirDiagnostic.NoElseInWhen