K2. Minor. Rename FirConstExpression to FirLiteralExpression

FirConstExpression is usually confused with "constant" calculations,
while in fact, it just denotes a simple literal expression
and `1 + 1` isn't represented by a FirConstExpression.

^KT-64314 Fixed

compiler/fir/dump/src/org/jetbrains/kotlin/fir/dump/HtmlFirDump.kt

@@ -759,7 +759,7 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
         }
     }
 
-    private fun FlowContent.generate(expression: FirConstExpression<*>) {
+    private fun FlowContent.generate(expression: FirLiteralExpression<*>) {
         val value = expression.value
         if (value == null && expression.kind != ConstantValueKind.Null) {
             return error {
@@ -1545,7 +1545,7 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
                 is FirElseIfTrueCondition -> generate(expression)
                 is FirWhenExpression -> generate(expression, isStatement = false)
                 is FirTryExpression -> generate(expression, isStatement = false)
-                is FirConstExpression<*> -> generate(expression)
+                is FirLiteralExpression<*> -> generate(expression)
                 is FirReturnExpression -> {
                     span("return-label") {
                         symbolRef(expression.target.labeledElement.symbol) {