doc: fix code

next/language/methods.md

@@ -4,10 +4,10 @@
 
 MoonBit supports methods in a different way from traditional object-oriented languages. A method in MoonBit is just a toplevel function associated with a type constructor. Methods can be defined using the syntax `fn TypeName::method_name(...) -> ...`:
 
-```{literalinclude} /sources/language/src/method/top.mbt
+```{literalinclude} /sources/language/src/method2/top.mbt
 :language: moonbit
-:start-after: start method 1
-:end-before: end method 1
+:start-after: start method 7
+:end-before: end method 7
 ```
 
 As a convenient shorthand, when the first parameter of a function is named `self`, MoonBit automatically defines the function as a method of the type of `self`:

next/sources/language/src/method/top.mbt

@@ -1,10 +1,10 @@
 // start method 1
-enum List[X] {
+pub(all) enum List[X] {
   Nil
   Cons(X, List[X])
 }
 
-fn List::concat[X](xs : List[List[X]]) -> List[X] {
+pub fn List::concat[X](xs : List[List[X]]) -> List[X] {
   ...
 }
 // end method 1

next/sources/language/src/method2/top.mbt

@@ -1,8 +1,14 @@
+// start method 7
 enum List[X] {
   Nil
   Cons(X, List[X])
 }
 
+fn List::concat[X](xs : List[List[X]]) -> List[X] {
+  ...
+}
+// end method 7
+
 // start method 3
 fn map[X, Y](self : List[X], f : (X) -> Y) -> List[Y] {
   ...