Write more on finite height lattices

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

content/blog/02_spa_agda_combining_lattices.md

@@ -425,7 +425,7 @@ we can create the infinite chain:
 
 On the other hand, our sign lattice _is_ of finite height; the longest chains
 we can make have three elements and two `<` signs. Here's one:
-{#sign-length-three}
+{#sign-three-elements}
 
 {{< latex >}}
 \bot < + < \top