FIR: Convert couple of methods to block-body

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/coneDiagnosticToFirDiagnostic.kt

@@ -163,7 +163,8 @@ private fun mapSystemHasContradictionError(
     diagnostic: ConeConstraintSystemHasContradiction,
     source: FirSourceElement,
     qualifiedAccessSource: FirSourceElement?,
-): List<FirDiagnostic<FirSourceElement>> = buildList<FirDiagnostic<FirSourceElement>> {
+): List<FirDiagnostic<FirSourceElement>> {
+    return buildList<FirDiagnostic<FirSourceElement>> {
         for (error in diagnostic.candidate.system.errors) {
             addIfNotNull(error.toDiagnostic(source, qualifiedAccessSource, diagnostic.candidate.callInfo.session.typeContext))
         }
@@ -180,12 +181,14 @@ private fun mapSystemHasContradictionError(
             }
         )
     }
+}
 
 private fun ConstraintSystemError.toDiagnostic(
     source: FirSourceElement,
     qualifiedAccessSource: FirSourceElement?,
     typeContext: ConeTypeContext,
-): FirDiagnostic<FirSourceElement>? = when (this) {
+): FirDiagnostic<FirSourceElement>? {
+    return when (this) {
         is NewConstraintError -> {
             val position = position.from
             val argument =
@@ -224,6 +227,7 @@ private fun ConstraintSystemError.toDiagnostic(
         }
         else -> null
     }
+}
 
 private val NewConstraintError.lowerConeType: ConeKotlinType get() = lowerType as ConeKotlinType
 private val NewConstraintError.upperConeType: ConeKotlinType get() = upperType as ConeKotlinType