Document slot machine more (unabridged)

src/scrcmd.c

@@ -1916,9 +1916,9 @@ bool8 ScrCmd_pokemartdecoration2(struct ScriptContext *ctx)
 
 bool8 ScrCmd_playslotmachine(struct ScriptContext *ctx)
 {
-    u8 slotMachineIndex = VarGet(ScriptReadHalfword(ctx));
+    u8 machineId = VarGet(ScriptReadHalfword(ctx));
 
-    PlaySlotMachine(slotMachineIndex, CB2_ReturnToFieldContinueScriptPlayMapMusic);
+    PlaySlotMachine(machineId, CB2_ReturnToFieldContinueScriptPlayMapMusic);
     ScriptContext1_Stop();
     return TRUE;
 }