Add @SinceKotlin and KDoc for ContextFunctionTypeParams

Initially, it was added accidentally as part of e3f987459c
and missed all out processes.

Adding @SinceKotlin("1.7") after the annotation has already been
published before is not really a problem, because it only may be used
with an experimental `-Xcontext-receivers` flag, thus it doesn't have
to be a part of our regular backward compatibility routine.

^KT-55226 Fixed

compiler/testData/builtin-classes/java6/kotlin.txt

@@ -208,7 +208,7 @@ public interface Comparable</*0*/ in T> {
     public abstract operator fun compareTo(/*0*/ other: T): kotlin.Int
 }
 
-@kotlin.annotation.Target(allowedTargets = {AnnotationTarget.TYPE}) @kotlin.annotation.MustBeDocumented public final annotation class ContextFunctionTypeParams : kotlin.Annotation {
+@kotlin.annotation.Target(allowedTargets = {AnnotationTarget.TYPE}) @kotlin.annotation.MustBeDocumented @kotlin.SinceKotlin(version = "1.7") public final annotation class ContextFunctionTypeParams : kotlin.Annotation {
     /*primary*/ public constructor ContextFunctionTypeParams(/*0*/ count: kotlin.Int)
     public final val count: kotlin.Int
         public final fun `<get-count>`(): kotlin.Int