Improved desc.

doc/src/ch02-lang/ch04-macros/ch01-builtins.md

@@ -171,6 +171,6 @@ push 0x08
 # assert_eq!(output, &[0x60, 0x08]);
 ```
 
-can only be compiled by specifying a hardfork using the `--hardfork` flag (the latest hardfork available by default) strictly after `London` and equal or older than `Cancun`.
+can only be compiled by specifying a hardfork using the `--hardfork` flag (with the latest hardfork available as the default option) strictly after `London` and equal or older than `Cancun`. Non-closed ranges can also be used, as well as specific versions (e.g. `%hardfork(">london")`, `%hardfork("cancun")` and `%hardfork(">=cancun,<=cancun")` are all valids.`).
 
 [abi]: https://docs.soliditylang.org/en/latest/abi-spec.html#function-selector