Docs for Pokémon mini, other bits.

Renamed the Pokémon mini doc to match internal name.

doc/7-systems/README.md

@@ -27,7 +27,7 @@ this is a list of sound chips that Furnace supports, including effects.
 - [PC Engine/TurboGrafx-16](pce.md)
 - [PC Speaker](pcspkr.md)
 - [Philips SAA1099](saa1099.md)
-- [Pokémon mini](pokemon.md)
+- [Pokémon mini](pokemini.md)
 - [Capcom QSound](qsound.md)
 - [Ricoh RF5C68](ricoh.md)
 - [SegaPCM](segapcm.md)

doc/7-systems/game-boy.md

@@ -2,7 +2,7 @@
 
 the Nintendo Game Boy is one of the most successful portable game systems ever made.
 
-with stereo sound, two pulse channels, a wave channel and a noise one it packed some serious punch.
+with stereo sound, two pulse channels, a wave channel and a noise channel, it packed some serious punch.
 
 # effects
 
@@ -20,3 +20,9 @@ with stereo sound, two pulse channels, a wave channel and a noise one it packed
   - `y` is the shift.
   - set to `0` to disable it.
 - `14xx`: **set sweep direction.** `0` is up and `1` is down.
+
+# links
+
+- [Gameboy sound hardware](https://gbdev.gg8.se/wiki/articles/Gameboy_sound_hardware) - detailed technical information
+
+- [GameBoy Sound Table](http://www.devrs.com/gb/files/sndtab.html) - note frequency table