Rename tgapi request structs

Add MaybeInaccessibleMessage tests and godoc
Update wiki and Bot API docs for the new naming

tgapi/games_types.go

@@ -1,5 +1,15 @@
 package tgapi
 
+type Game struct {
+	Title        string          `json:"title"`
+	Description  string          `json:"description"`
+	Photo        []PhotoSize     `json:"photo"`
+	Text         string          `json:"text,omitempty"`
+	TextEntities []MessageEntity `json:"text_entities,omitempty"`
+	Animation    *Animation      `json:"animation,omitempty"`
+}
+type CallbackGame struct{}
+
 // GameHighScore represents one row in a game high score table.
 // See https://core.telegram.org/bots/api#gamehighscore
 type GameHighScore struct {