caps is so important

Co-authored-by: Michael Goulet <michael@errs.io>

src/early-late-bound.md

@@ -14,7 +14,7 @@ with this topic.
 
 ## What does it mean for parameters to be early or late bound
 
-All function definitions conceptually have a zst (this is represented by `TyKind::FnDef` in rustc).
+All function definitions conceptually have a ZST (this is represented by `TyKind::FnDef` in rustc).
 The only generics on this zst are the early bound parameters of the function definition. e.g.
 ```rust
 fn foo<'a>(_: &'a u32) {}