remove outdated text about wfx implies

Author: patrickoliveira15

src/solve/invariants.md

@@ -16,16 +16,6 @@ of these cases
 - ❌: this invariant does not hold, either due to bugs or by design, you must not rely on
 it for soundness or have to be incredibly careful when doing so
 
-### `wf(X)` implies `wf(normalize(X))` ✅
-
-If a type containing aliases is well-formed, it should also be
-well-formed after normalizing said aliases. We rely on this as
-otherwise we would have to re-check for well-formedness for these
-types.
-
-This is unfortunately broken for `<fndef as FnOnce<..>>::Output` due to implied bounds,
-resulting in [#114936].
-
 ### Structural equality modulo regions implies semantic equality ✅
 
 If you have a some type and equate it to itself after replacing any regions with unique