doc: update README status

README.md

@@ -20,6 +20,7 @@ The goal is to produce idiomatic, maintainable Go code as part of a one-off conv
 	- [ ] Expr
 	- [X] Binary
 	- [ ] Scalar
+		- [ ] Heredocs/nowdocs
 [X] Array handling
 	- [X] Infer whether to use slice/map for PHP array
 	- [ ] Infer whether map use should be order-preserving
@@ -33,9 +34,9 @@ The goal is to produce idiomatic, maintainable Go code as part of a one-off conv
 [ ] Generators
 [ ] Numbered break/continue
 [ ] Goto
-[ ] Comma operator
-[ ] `null` -> `nil`
+[X] `null` -> `nil`
 [X] Consts and `define()`
+	- [X] Magic constants (`__LINE__`,`__FILE__` etc)
 [ ] `isset`/`unset`
 [ ] `instanceof`
 [X] `die`
@@ -73,6 +74,7 @@ The goal is to produce idiomatic, maintainable Go code as part of a one-off conv
 	- [ ] Traits / `use`
 	- [ ] Abstract methods
 [ ] Type inference
+	- [ ] Type declarations for literals (string, slice/map with constant initializer, etc)
 	- [ ] Convert known PHP typenames to Go equivalents
 	- [ ] Parse extra types from phpdoc blocks
 [ ] Infer whether to declare variable (`var` / `:=`) or reuse (`=`)