Added u128 & i128 under integer literals

Also sorted `usize` & `isize` to match the sorting of other literals.

Author: markmmm

src/tokens.md

@@ -350,7 +350,7 @@ Like any literal, an integer literal may be followed (immediately,
 without any spaces) by an _integer suffix_, which forcibly sets the
 type of the literal. The integer suffix must be the name of one of the
 integral types: `u8`, `i8`, `u16`, `i16`, `u32`, `i32`, `u64`, `i64`,
-`isize`, or `usize`.
+`u128`, `i128`, `usize`, or `isize`.
 
 The type of an _unsuffixed_ integer literal is determined by type inference: