Update manual and changelog in regards to gunpowder barrels

Author: BluSunrize

src/main/resources/assets/immersiveengineering/manual/en_us/gunpowder_barrels.txt

@@ -1,5 +1,7 @@
 Gunpowder Barrels
 Volatile, Yet Decorative
 <&recipe>Gunpowder can be made into TNT and other explosives, but these are hard to control and impractical for mining.<br>
-By containing black powder in a <link;storage_barrels;Wooden Barrel>, powder barrels allow for more bang for buck.<br>
-Gunpowder Barrels work as mining explosives with a more predictable explosion that do not destroy items.
+By containing black powder in a <link;storage_barrels;Wooden Barrel>, powder barrels allow for more bang for buck.<np>
+Gunpowder Barrels work as mining explosives with a very predictable explosion that do not destroy items.
+The regular shape of their explosive pattern makes them perfect for mining tunnels in particular.<br>
+Additionally, they inflict much higher damage to anything living nearby, so it's best to stay away from their explosions.