Fixed generic distinct conversions for 'var' (#18837)

* SameTypeAux now properly traverses generic distincts

* Smarter traversal of distincts

* Removed redundant check

* Fixed nkConv for jsgen

* Added test for non distinct nkConv

* using skiptypes for distinct now

* Fixed genaddr for nkconv

tests/converter/texplicit_conversion.nim

@@ -11,3 +11,9 @@ converter toInt(s: string): int =
 
 let x = (int)"234"
 echo x
+
+block: # Test for nkconv
+  proc foo(o: var int) =
+    assert o == 0
+  var a = 0
+  foo(int(a))