[Analysis API FIR] Fix small mistake in KDocReferenceResolver

`owner` is a PSI element, it can never be an instance of
`KtConstructorSymbol`

Also, make `MutableCollection` an extension receiver instead of context
receiver for the consistency

analysis/analysis-api/testData/referenceResolve/kDoc/parameters/ConstructorValueParameter.kt

@@ -1,7 +1,3 @@
-// TODO
-// UNRESOLVED_REFERENCE
-
-
 class C {
     /**
      * [a<caret>a]