[FIR IDE] LC Add KtFileSymbol and fix facade annotations

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/KtAnalysisSession.kt

@@ -121,6 +121,8 @@ abstract class KtAnalysisSession(final override val token: ValidityToken) : Vali
 
     fun KtPropertyAccessor.getPropertyAccessorSymbol(): KtPropertyAccessorSymbol = symbolProvider.getPropertyAccessorSymbol(this)
 
+    fun KtFile.getFileSymbol(): KtFileSymbol = symbolProvider.getFileSymbol(this)
+
     /**
      * @return symbol with specified [this@getClassOrObjectSymbolByClassId] or `null` in case such symbol is not found
      */

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/KtFileSymbol.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.frontend.api.symbols
+
+import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtAnnotatedSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtSymbolPointer
+
+abstract class KtFileSymbol : KtAnnotatedSymbol {
+    abstract override fun createPointer(): KtSymbolPointer<KtFileSymbol>
+}

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/KtSymbolProvider.kt

@@ -30,6 +30,7 @@ abstract class KtSymbolProvider : KtAnalysisSessionComponent() {
     }
 
     abstract fun getParameterSymbol(psi: KtParameter): KtParameterSymbol
+    abstract fun getFileSymbol(psi: KtFile): KtFileSymbol
     abstract fun getFunctionSymbol(psi: KtNamedFunction): KtFunctionSymbol
     abstract fun getConstructorSymbol(psi: KtConstructor<*>): KtConstructorSymbol
     abstract fun getTypeParameterSymbol(psi: KtTypeParameter): KtTypeParameterSymbol