Drop redundant butNot = Param clause in isAnchor

[Cherry-picked 9d88c80][modified]

Author: WojciechMazur

compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -596,7 +596,7 @@ trait ImplicitRunInfo:
   private def isAnchor(sym: Symbol) =
     sym.isClass && !isExcluded(sym)
     || sym.isOpaqueAlias
-    || sym.is(Deferred, butNot = Param)
+    || sym.is(Deferred)
     || sym.info.isInstanceOf[MatchAlias]
 
   private def computeIScope(rootTp: Type): OfTypeImplicits =