feat(journal): update start of week 4 day 2

journal/tapl_progress.typ

@@ -126,6 +126,7 @@
     depends-on: (20, 15),
   ),
   "22": (
+    state: "current",
     pos: (4.5, 4),
     depends-on: (11,),
   ),

journal/week4.typ

@@ -8,3 +8,9 @@
 - Show type checker diagnostics
 - Update VSCode syntax highlighting extension
 - Add support for if statements and ternary expressions
+
+#day(2)
+
+- Read TAPL (22)
+- Rework abstract types
+- Generalize syntax (more modularity for generics, unions, constraints, etc.)