tests: Trim .nim files trailing whitespace

via OSX: find . -name '*.nim' -exec sed -i '' -E 's/[[:space:]]+$//' {} +

tests/effects/teffects6.nim

@@ -3,7 +3,7 @@ type
   PMenu = ref object
   PMenuItem = ref object
 
-proc createMenuItem*(menu: PMenu, label: string, 
+proc createMenuItem*(menu: PMenu, label: string,
                     action: proc (i: PMenuItem, p: pointer) {.cdecl.}) = discard
 
 var s: PMenu
@@ -19,7 +19,7 @@ createMenuItem(s, "Go to definition...",
 proc noRaise(x: proc()) {.raises: [].} =
   # unknown call that might raise anything, but valid:
   x()
-  
+
 proc doRaise() {.raises: [EIO].} =
   raise newException(EIO, "IO")