feat: execute existing hash maps through Honey

source/lexer/scan.hon

@@ -29,6 +29,7 @@ keywords strmap.StaticStringMap(TokenKind) :: strmap.init([
     { "yield", .yield },
     { "break", .break },
     { "continue", .continue },
+    { "unreachable", .unreachable },
     { "try", .try },
     { "catch", .catch },
     { "defer", .defer },

source/lexer/token.hon

@@ -25,6 +25,7 @@ TokenKind :: enum {
     proc, return
     yield
     break, continue
+    unreachable
     try, catch
     defer, errdefer
     true, false