Update leaderboard-rules regarding non-built-in timers.md (#84)

Co-authored-by: Andrew Farkas <6060305+HactarCE@users.noreply.github.com>

Author: OtaMota

docs/leaderboard-rules.md

@@ -38,6 +38,7 @@ These rules apply generally to speedsolving submissions unless the category has
 - Inspection time must not exceed 60 seconds. Penalty: disqualification of the attempt (DNF).
     - When using HSC2, solve time starts automatically after 60 seconds of inspection to avoid a DNF.
     - In other software or when solving physical puzzles, the solve will be rejected if inspection time exceeds 60 seconds.
+- The timer must start on or before the first move.[^timer]
 - If any moves are executed on the solved puzzle shortly after the timer stops, the moderators may retime or reject the solve at their discretion.
 
 ### Replay files
@@ -154,6 +155,7 @@ If you're thinking of writing a new program for speedsolving or suggesting a new
 [stm]: https://hypercubing.xyz/notation/#turn-metrics
 
 [^algsheets]: We can't stop you from using an algorithm reference, but it's not in the spirit of the competition and it'll probably slow you down.
+[^timer]: If a built-in timer that starts automatically after the first move is not available, a self-supplied timer from the compeitior may be used instead, and the time starts when the compeitior manually starts the timer.
 [^keybinds-ref]: If the program doesn't have a built-in keybinds reference (such as Akkei's physical 3^4^ simulator) then you probably don't need one.
 [^alg-keybinds]: You should not be able to execute a meaningful algorithm by pressing a sequence of keys in a line on the keyboard. Keybinds should be laid out in a way that makes more sense than a way that is useful for an algorithm. A keybind set optimized for general RKT is fine. If you have a question about these rules, ask on the [Hypercubers Discord server](https://discord.gg/xxFvfyx89p).
 [^grip]: You might hold a 3^3^ differently to execute `<M,U>` moves more efficiently compared to `<R,U,F>` moves. Similarly, a 4D creature might have a specialized grip on the 3^4^ for RKT compared to general moves.