Add game 'life' api reference (#1569)

docs/reference/game/set-life.md

@@ -0,0 +1,26 @@
+# set Life
+
+Set the game life count to this amount.
+
+```sig
+game.setLife(0)
+```
+
+Your program has a life counter which you can set to record the number of lives remaining for a player in your game. If you set the life count to `0` or less, the game ends.
+
+## Parameters
+
+* **value**: a [number](/types/number) to set the life count to.
+
+## Example #example
+
+Set the player life count to `9` lives before starting the game.
+
+```blocks
+game.setLife(9)
+```
+
+## See also #seealso
+
+[add life](/reference/game/add-life),
+[remove life](/reference/game/remove-life)