Reduce dependence on the internal dictionary passing mechanism

Part of this work was done by @the-dr-lazy in
https://github.com/ajnsit/purescript-typeable/pull/3.

GOOD:
Now there is no more dependence on dictionaries being passed as function
arguments at runtime.

BAD:
1. However, we still depend on the dictionaries being stable at runtime.
2. We now also assume that the output of the new function `makeTag` will
never be cached.

.gitignore

@@ -8,3 +8,4 @@
 /.purs*
 /.psa*
 /.spago
+.pnpm-debug.log