update mbtis

builtin/builtin.mbti

@@ -67,7 +67,7 @@ fn Byte::to_int(Byte) -> Int
 fn Byte::to_string(Byte) -> String
 fn Char::compare(Char, Char) -> Int
 fn Char::default() -> Char
-fn Char::from_int(Int) -> Char
+fn Char::from_int_unchecked(Int) -> Char
 fn Char::op_equal(Char, Char) -> Bool
 fn Char::to_int(Char) -> Int
 fn Int::asr(Int, Int) -> Int

char/char.mbti

@@ -1,10 +1,15 @@
 package moonbitlang/core/char
 
 // Values
+let max : Char
+
+let min : Char
 
 // Types and methods
 fn Char::debug_write(Char, Buffer) -> Unit
+fn Char::from_int(Int) -> Option[Char]
 fn Char::hash(Char) -> Int
+fn Char::is_valid(Char) -> Bool
 fn Char::to_string(Char) -> String
 
 // Traits