Improve support of custom equals in inline classes

- Ensure that typed equals parameter's type is a star projection of
  corresponding inline class

- Make possible to declare typed equals that returns 'Nothing'

- Forbid type parameters in typed equals operator declaration

^KT-54909 fixed
^KT-54910 fixed

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

@@ -3884,7 +3884,7 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
     }
     add(FirErrors.INEFFICIENT_EQUALS_OVERRIDING_IN_INLINE_CLASS) { firDiagnostic ->
         InefficientEqualsOverridingInInlineClassImpl(
-            firDiagnostic.a,
+            firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.a),
             firDiagnostic as KtPsiDiagnostic,
             token,
         )

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

@@ -2710,7 +2710,7 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
 
     abstract class InefficientEqualsOverridingInInlineClass : KtFirDiagnostic<KtNamedFunction>() {
         override val diagnosticClass get() = InefficientEqualsOverridingInInlineClass::class
-        abstract val className: String
+        abstract val type: KtType
     }
 
     abstract class CannotAllUnderImportFromSingleton : KtFirDiagnostic<KtImportDirective>() {

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

@@ -3267,7 +3267,7 @@ internal class RedundantInlineSuspendFunctionTypeImpl(
 ) : KtFirDiagnostic.RedundantInlineSuspendFunctionType(), KtAbstractFirDiagnostic<KtElement>
 
 internal class InefficientEqualsOverridingInInlineClassImpl(
-    override val className: String,
+    override val type: KtType,
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: KtLifetimeToken,
 ) : KtFirDiagnostic.InefficientEqualsOverridingInInlineClass(), KtAbstractFirDiagnostic<KtNamedFunction>