Fix patterns grab recursion

src/syndicate/patterns.nim

@@ -103,7 +103,7 @@ proc grab*[T](pr: Value): Pattern =
   else:
     raise newException(ValueError, "cannot generate a pattern for unhandled Value type")
 
-proc grab*[T](val: T): Pattern =
+proc grab*[T](x: T): Pattern =
   ## Construct a `Pattern` from value of type `T`.
   runnableExamples:
     from std/unittest import check
@@ -111,7 +111,7 @@ proc grab*[T](val: T): Pattern =
       $grab(true) == "<lit #t>"
       $grab(3.14) == "<lit 3.14>"
       $grab([0, 1, 2, 3]) == "<arr [<lit 0> <lit 1> <lit 2> <lit 3>]>"
-  grab(val)
+  grab(x.toPreserves)
 
 proc patternOfType(typ: static typedesc; `bind`: static bool): Pattern =
   when typ is ref: