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/distinct/tdistinct.nim

@@ -8,6 +8,7 @@ false
 false
 false
 Foo
+foo
 '''
 """
 
@@ -140,6 +141,22 @@ block tRequiresInit:
     let s = "test"
     doAssert s == "test"
 
+block: #17322
+  type
+    A[T] = distinct string
+
+  proc foo(a: var A) =
+    a.string.add "foo"
+
+  type
+    B = distinct A[int]
+
+  var b: B
+  foo(A[int](b))
+  echo A[int](b).string
+  b.string.add "bar"
+  assert b.string == "foobar"
+
 type Foo = distinct string
 
 template main() =