Minor change to leaderboards.md: Clarification of game speed hint (#291)

* Update leaderboards.md

Remove confusing part of sentence

* Update leaderboard documentation for frame rate details

Clarify the frame rate context for the leaderboard type.

* Fix link in leaderboards documentation

Updated link in the Type section for clarity.

Author: akleemans

docs/developer-docs/leaderboards.md

@@ -55,7 +55,7 @@ The best place to start is to look at existing leaderboards and break it down to
 
 The **Title/Description** fields are quite obvious.
 
-The **Type** is "Time (Frames)". The value we're tracking updates once a frame, and the Genesis runs at 60 frames per second. (see not below for systems that run at other speeds)
+The **Type** is "Time (Frames)". The value we're tracking updates once a frame, and the Genesis runs at 60 frames per second (see note below on [Value Format](/developer-docs/leaderboards#value-format) for systems that run at other speeds).
 
 The **Lower Is Better** flag is checked, then the one who makes the shortest time will be the #1.